[PATCH v9 00/41] guest_memfd: In-place conversion support

[PATCH v9 00/41] guest_memfd: In-place conversion support

[Ackerley Tng via B4 Relay]

This is v9 of guest_memfd in-place conversion support. Please find the
motivation for this series from v8 and before.

Here are the changes from v8->v9:

+ Ordering changes: Reverted to the v7 and
  github/sean-jc/linux/x86/gmem_inplace ordering.
     + Xiaoyao/Sean, hope this works better.
+ For Sean (since github/sean-jc/linux/x86/gmem_inplace was never on-list)
    + Extracted these patches out of your "KVM: guest_memfd: Wire up
      core per-gmem attribute interfaces" to have the wiring up patch
      focus on wiring up.
	    + "KVM: guest_memfd: Introduce function to check GFN
          private/shared status"
        + "guest_memfd: Introduce function to check GFN private/shared
          status"
    + Moved the patches that allow conversions for TDX and SNP after
      the TDX and SNP changes to make source addr optional, so that
      once conversions can be used with TDX they will work.
    + Added to the description of "KVM: Let userspace disable per-VM
      mem attributes, enable per-gmem attributes" to explain the
      components of the change better.
+ Centralized interpretation of a maple tree entry - the part where
  guest_memfd will default to the initial shared/private state if
  entry is NULL - into kvm_gmem_interpret_entry().
+ "KVM: selftests: Add support for mmap() on guest_memfd in core library"
    + For guest_memfd, always mmap with MAP_SHARED. guest_memfd only
      supports MAP_SHARED.
	+ Dropped "KVM: selftests: Check fd/flags provided to mmap() when
      setting up memslot" [1], since it was meant to check that when a
      guest_memfd is used as region->fd, the flag provided to mmap()
      will include MAP_SHARED.
+ "KVM: guest_memfd: Wire up core private/shared attribute interfaces"
    + Renamed kvm_gmem_range_is_private() to kvm_range_is_private()
      since this function checks both VM and guest_memfd attributes.
+ Dropped "Use actual size for invalidation in kvm_gmem_release()"
  since now the invalidation logic doesn't determine filter based on
  range. Only zap pages not already in the desired state. [Suzuki]
+ To address Vlastimil and David's comments [2] on freezing refcounts,
  in this patch series we're checking for safe refcounts to ensure
  that there are no other users of the memory. For this series, we can
  tolerate speculative bump+release of the refcounts, since those
  don't access memory. I'll definitely re-look refcount freezing when
  we get to the point that we need to restructure (split/merge) huge
  pages. Thanks!
+ Addressed the other comments from v8

Tested with both CONFIG_KVM_VM_MEMORY_ATTRIBUTES enabled and disabled:

+ tools/testing/selftests/kvm/guest_memfd_test.c
+ tools/testing/selftests/kvm/pre_fault_memory_test.c
+ tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+ tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
+ tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c

This series is based on kvm-x86/next, and here's the tree for your convenience:

https://github.com/googleprodkernel/linux-cc/commits/guest_memfd-inplace-conversion-v9

I tested v9 with CoCo selftests on top of the branch above:

https://github.com/googleprodkernel/linux-cc/commits/guest_memfd-inplace-conversion-coco-selftests-v9

Older series:

v8: https://lore.kernel.org/r/20260618-gmem-inplace-conversion-v8-0-9d2959357853@google.com
v7: https://lore.kernel.org/r/20260522-gmem-inplace-conversion-v7-0-2f0fae496530@google.com
v6: https://lore.kernel.org/r/20260507-gmem-inplace-conversion-v6-0-91ab5a8b19a4@google.com
RFC v5: https://lore.kernel.org/r/20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com
RFC v4: https://lore.kernel.org/all/20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com/T/
RFC v3: https://lore.kernel.org/r/20260313-gmem-inplace-conversion-v3-0-5fc12a70ec89@google.com/T/
RFC v2: https://lore.kernel.org/all/cover.1770071243.git.ackerleytng@google.com/T/
RFC v1: https://lore.kernel.org/all/cover.1760731772.git.ackerleytng@google.com/T/

Previous versions of this feature, part of other series, are available at:

+ https://lore.kernel.org/all/bd163de3118b626d1005aa88e71ef2fb72f0be0f.1726009989.git.ackerleytng@google.com/
+ https://lore.kernel.org/all/20250117163001.2326672-6-tabba@google.com/
+ https://lore.kernel.org/all/b784326e9ccae6a08388f1bf39db70a2204bdc51.1747264138.git.ackerleytng@google.com/

[1] https://lore.kernel.org/all/20260618-gmem-inplace-conversion-v8-43-9d2959357853@google.com/
[2] https://lore.kernel.org/all/088e9969-9104-4163-8ad4-59bec96014e0@kernel.org/

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
Ackerley Tng (23):
      KVM: guest_memfd: Introduce function to check GFN private/shared status
      KVM: guest_memfd: Filter both shared and private when invalidating
      KVM: guest_memfd: Add base support for KVM_SET_MEMORY_ATTRIBUTES2
      KVM: guest_memfd: Ensure pages are not in use before conversion
      KVM: guest_memfd: Call arch make_shared callback for to-shared conversion
      KVM: guest_memfd: Return early if range already has requested attributes
      mm: swap: Introduce lru_add_drain_progressive()
      KVM: guest_memfd: Handle lru_add fbatch refcounts during conversion safety check
      KVM: guest_memfd: Zero page while getting pfn
      KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
      KVM: Let userspace disable per-VM mem attributes, enable per-gmem attributes
      KVM: selftests: Test basic single-page conversion flow
      KVM: selftests: Test conversion flow when INIT_SHARED
      KVM: selftests: Test conversion precision in guest_memfd
      KVM: selftests: Test conversion before allocation
      KVM: selftests: Convert with allocated folios in different layouts
      KVM: selftests: Test that truncation does not change shared/private status
      KVM: selftests: Add helpers to pin pages with CONFIG_GUP_TEST
      KVM: selftests: Test conversion with elevated page refcount
      KVM: selftests: Reset shared memory after hole-punching
      KVM: selftests: Provide function to look up guest_memfd details from gpa
      KVM: selftests: Make TEST_EXPECT_SIGBUS thread-safe
      KVM: selftests: Update private_mem_conversions_test to mmap() guest_memfd

Michael Roth (1):
      KVM: SEV: Make 'uaddr' parameter optional for KVM_SEV_SNP_LAUNCH_UPDATE

Sean Christopherson (17):
      KVM: guest_memfd: Introduce per-gmem attributes, use to guard user mappings
      KVM: Rename KVM_GENERIC_MEMORY_ATTRIBUTES to KVM_VM_MEMORY_ATTRIBUTES
      KVM: Enumerate support for PRIVATE memory iff kvm_arch_has_private_mem is defined
      KVM: Rename memory attribute APIs to prepare for in-place gmem conversion
      KVM: Provide generic interface for checking memory private/shared status
      KVM: guest_memfd: Wire up core private/shared attribute interfaces
      KVM: Consolidate private memory and guest_memfd ifdeffery in kvm_host.h
      KVM: Move KVM_VM_MEMORY_ATTRIBUTES config definition to x86
      KVM: guest_memfd: Enable INIT_SHARED on guest_memfd for x86 Coco VMs
      KVM: selftests: Create gmem fd before "regular" fd when adding memslot
      KVM: selftests: Rename guest_memfd{,_offset} to gmem_{fd,offset}
      KVM: selftests: Add support for mmap() on guest_memfd in core library
      KVM: selftests: Add selftests global for guest memory attributes capability
      KVM: selftests: Add helpers for calling ioctls on guest_memfd
      KVM: selftests: Test that shared/private status is consistent across processes
      KVM: selftests: Provide common function to set memory attributes
      KVM: selftests: Update private memory exits test to work with per-gmem attributes

 Documentation/virt/kvm/api.rst                     |  78 +++-
 .../virt/kvm/x86/amd-memory-encryption.rst         |  14 +-
 Documentation/virt/kvm/x86/intel-tdx.rst           |   4 +
 arch/x86/include/asm/kvm-x86-ops.h                 |   2 +-
 arch/x86/include/asm/kvm_host.h                    |   6 +-
 arch/x86/kvm/Kconfig                               |  15 +-
 arch/x86/kvm/mmu/mmu.c                             |  16 +-
 arch/x86/kvm/svm/sev.c                             |  11 +-
 arch/x86/kvm/vmx/tdx.c                             |   8 +-
 arch/x86/kvm/x86.c                                 |  20 +-
 include/linux/kvm_host.h                           |  76 +--
 include/linux/swap.h                               |   2 +
 include/trace/events/kvm.h                         |   6 +-
 include/uapi/linux/kvm.h                           |  16 +
 mm/gup.c                                           |  19 +-
 mm/swap.c                                          |  17 +
 tools/testing/selftests/kvm/Makefile.kvm           |   1 +
 tools/testing/selftests/kvm/include/kvm_util.h     | 139 +++++-
 tools/testing/selftests/kvm/include/test_util.h    |  34 +-
 tools/testing/selftests/kvm/lib/kvm_util.c         | 164 ++++---
 tools/testing/selftests/kvm/lib/test_util.c        |   7 -
 .../kvm/x86/guest_memfd_conversions_test.c         | 509 +++++++++++++++++++++
 .../kvm/x86/private_mem_conversions_test.c         |  53 ++-
 .../selftests/kvm/x86/private_mem_kvm_exits_test.c |  36 +-
 virt/kvm/Kconfig                                   |   3 -
 virt/kvm/guest_memfd.c                             | 465 +++++++++++++++++--
 virt/kvm/kvm_main.c                                |  92 ++--
 27 files changed, 1551 insertions(+), 262 deletions(-)
---
base-commit: 3c7d7f908d574277a845423ec32250a8d8df44c8
change-id: 20260225-gmem-inplace-conversion-bd0dbd39753a

Best regards,
--
Ackerley Tng <ackerleytng@google.com>

[PATCH v9 01/41] KVM: guest_memfd: Introduce per-gmem attributes, use to guard user mappings

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Start plumbing in guest_memfd support for in-place private<=>shared
conversions by tracking attributes via a maple tree.  KVM currently tracks
private vs. shared attributes on a per-VM basis, which made sense when a
guest_memfd _only_ supported private memory, but tracking per-VM simply
can't work for in-place conversions as the shared/private status of a given
page needs to be per-gmem_inode, not per-VM.

Use the filemap invalidation lock to protect the maple tree, as taking the
lock for read when faulting in memory (for userspace or the guest) isn't
expected to result in meaningful contention, and using a separate lock
would add significant complexity (avoiding deadlock is quite difficult).

Co-developed-by: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Co-developed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 virt/kvm/guest_memfd.c | 133 ++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 116 insertions(+), 17 deletions(-)

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 0bca42a0b346b..3d6547c5ba9a6 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -4,6 +4,7 @@
 #include <linux/falloc.h>
 #include <linux/fs.h>
 #include <linux/kvm_host.h>
+#include <linux/maple_tree.h>
 #include <linux/mempolicy.h>
 #include <linux/pseudo_fs.h>
 #include <linux/pagemap.h>
@@ -33,6 +34,13 @@ struct gmem_inode {
 	struct list_head gmem_file_list;
 
 	u64 flags;
+	/*
+	 * Every index in this inode, whether memory is populated or
+	 * not, is tracked in attributes. The entire range of indices,
+	 * corresponding to the size of this inode, is represented in
+	 * this maple tree.
+	 */
+	struct maple_tree attributes;
 };
 
 static __always_inline struct gmem_inode *GMEM_I(struct inode *inode)
@@ -60,9 +68,25 @@ static pgoff_t kvm_gmem_get_index(struct kvm_memory_slot *slot, gfn_t gfn)
 	return gfn - slot->base_gfn + slot->gmem.pgoff;
 }
 
+static u64 kvm_gmem_interpret_entry(struct inode *inode, void *entry)
+{
+	if (WARN_ON_ONCE(!entry)) {
+		bool initially_shared = GMEM_I(inode)->flags &
+					GUEST_MEMFD_FLAG_INIT_SHARED;
+
+		return initially_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE;
+	}
+
+	return xa_to_value(entry);
+}
+
 static bool kvm_gmem_is_private_mem(struct inode *inode, pgoff_t index)
 {
-	return !(GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_INIT_SHARED);
+	struct maple_tree *mt = &GMEM_I(inode)->attributes;
+	void *entry = mtree_load(mt, index);
+
+	return kvm_gmem_interpret_entry(inode, entry) &
+	       KVM_MEMORY_ATTRIBUTE_PRIVATE;
 }
 
 static bool kvm_gmem_is_shared_mem(struct inode *inode, pgoff_t index)
@@ -363,10 +387,13 @@ static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf)
 	if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode))
 		return VM_FAULT_SIGBUS;
 
-	if (!kvm_gmem_is_shared_mem(inode, vmf->pgoff))
-		return VM_FAULT_SIGBUS;
+	filemap_invalidate_lock_shared(inode->i_mapping);
+	if (kvm_gmem_is_shared_mem(inode, vmf->pgoff))
+		folio = kvm_gmem_get_folio(inode, vmf->pgoff);
+	else
+		folio = ERR_PTR(-EACCES);
+	filemap_invalidate_unlock_shared(inode->i_mapping);
 
-	folio = kvm_gmem_get_folio(inode, vmf->pgoff);
 	if (IS_ERR(folio)) {
 		if (PTR_ERR(folio) == -EAGAIN)
 			return VM_FAULT_RETRY;
@@ -519,6 +546,51 @@ bool __weak kvm_arch_supports_gmem_init_shared(struct kvm *kvm)
 	return true;
 }
 
+static int kvm_gmem_init_inode(struct inode *inode, loff_t size, u64 flags)
+{
+	struct gmem_inode *gi = GMEM_I(inode);
+	MA_STATE(mas, &gi->attributes, 0, (size >> PAGE_SHIFT) - 1);
+	u64 attrs;
+	int r;
+
+	inode->i_op = &kvm_gmem_iops;
+	inode->i_mapping->a_ops = &kvm_gmem_aops;
+	inode->i_mode |= S_IFREG;
+	inode->i_size = size;
+	mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
+
+	/*
+	 * guest_memfd memory is neither migratable nor swappable: set
+	 * inaccessible to gate off both.
+	 */
+	mapping_set_inaccessible(inode->i_mapping);
+	WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping));
+
+	gi->flags = flags;
+
+	mt_set_external_lock(&gi->attributes,
+			     &inode->i_mapping->invalidate_lock);
+
+	/*
+	 * Store default attributes for the entire gmem instance. Ensuring every
+	 * index is represented in the maple tree at all times simplifies the
+	 * conversion and merging logic.
+	 */
+	attrs = gi->flags & GUEST_MEMFD_FLAG_INIT_SHARED ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE;
+
+	/*
+	 * Acquire the invalidation lock purely to make lockdep happy.  The
+	 * maple tree library expects all stores to be protected via the lock,
+	 * and the library can't know when the tree is reachable only by the
+	 * caller, as is the case here.
+	 */
+	filemap_invalidate_lock(inode->i_mapping);
+	r = mas_store_gfp(&mas, xa_mk_value(attrs), GFP_KERNEL);
+	filemap_invalidate_unlock(inode->i_mapping);
+
+	return r;
+}
+
 static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
 {
 	static const char *name = "[kvm-gmem]";
@@ -549,16 +621,9 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
 		goto err_fops;
 	}
 
-	inode->i_op = &kvm_gmem_iops;
-	inode->i_mapping->a_ops = &kvm_gmem_aops;
-	inode->i_mode |= S_IFREG;
-	inode->i_size = size;
-	mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
-	mapping_set_inaccessible(inode->i_mapping);
-	/* Unmovable mappings are supposed to be marked unevictable as well. */
-	WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping));
-
-	GMEM_I(inode)->flags = flags;
+	err = kvm_gmem_init_inode(inode, size, flags);
+	if (err)
+		goto err_inode;
 
 	file = alloc_file_pseudo(inode, kvm_gmem_mnt, name, O_RDWR, &kvm_gmem_fops);
 	if (IS_ERR(file)) {
@@ -763,9 +828,13 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 	if (!file)
 		return -EFAULT;
 
+	filemap_invalidate_lock_shared(file_inode(file)->i_mapping);
+
 	folio = __kvm_gmem_get_pfn(file, slot, index, pfn, max_order);
-	if (IS_ERR(folio))
-		return PTR_ERR(folio);
+	if (IS_ERR(folio)) {
+		r = PTR_ERR(folio);
+		goto out;
+	}
 
 	if (!folio_test_uptodate(folio)) {
 		clear_highpage(folio_page(folio, 0));
@@ -785,6 +854,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 	else
 		folio_put(folio);
 
+out:
+	filemap_invalidate_unlock_shared(file_inode(file)->i_mapping);
 	return r;
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn);
@@ -916,6 +987,15 @@ static struct inode *kvm_gmem_alloc_inode(struct super_block *sb)
 
 	mpol_shared_policy_init(&gi->policy, NULL);
 
+	/*
+	 * Memory attributes are protected by the filemap invalidation lock, but
+	 * the lock structure isn't available at this time.  Immediately mark
+	 * maple tree as using external locking so that accessing the tree
+	 * before it's fully initialized results in NULL pointer dereferences
+	 * and not more subtle bugs.
+	 */
+	mt_init_flags(&gi->attributes, MT_FLAGS_LOCK_EXTERN | MT_FLAGS_USE_RCU);
+
 	gi->flags = 0;
 	INIT_LIST_HEAD(&gi->gmem_file_list);
 	return &gi->vfs_inode;
@@ -923,7 +1003,26 @@ static struct inode *kvm_gmem_alloc_inode(struct super_block *sb)
 
 static void kvm_gmem_destroy_inode(struct inode *inode)
 {
-	mpol_free_shared_policy(&GMEM_I(inode)->policy);
+	struct gmem_inode *gi = GMEM_I(inode);
+
+	mpol_free_shared_policy(&gi->policy);
+
+	/*
+	 * Note!  Checking for an empty tree is functionally necessary
+	 * to avoid explosions if the tree hasn't been fully
+	 * initialized, i.e. if the inode is being destroyed before
+	 * guest_memfd can set the external lock, lockdep would find
+	 * that the tree's internal ma_lock was not held.
+	 */
+	if (!mtree_empty(&gi->attributes)) {
+		/*
+		 * Acquire the invalidation lock purely to make lockdep happy,
+		 * the inode is unreachable at this point.
+		 */
+		filemap_invalidate_lock(inode->i_mapping);
+		__mt_destroy(&gi->attributes);
+		filemap_invalidate_unlock(inode->i_mapping);
+	}
 }
 
 static void kvm_gmem_free_inode(struct inode *inode)

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 02/41] KVM: Rename KVM_GENERIC_MEMORY_ATTRIBUTES to KVM_VM_MEMORY_ATTRIBUTES

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Rename the per-VM memory attributes Kconfig to make it explicitly about
per-VM attributes in anticipation of adding memory attributes support to
guest_memfd, at which point it will be possible (and desirable) to have
memory attributes without the per-VM support, even in x86.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/Kconfig            |  6 +++---
 arch/x86/kvm/mmu/mmu.c          |  2 +-
 arch/x86/kvm/x86.c              |  2 +-
 include/linux/kvm_host.h        |  8 ++++----
 include/trace/events/kvm.h      |  4 ++--
 virt/kvm/Kconfig                |  2 +-
 virt/kvm/kvm_main.c             | 14 +++++++-------
 8 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7a258831616fa..9fdf13b071097 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1849,7 +1849,7 @@ enum kvm_intr_type {
 	((vcpu) && (vcpu)->arch.handling_intr_from_guest && \
 	 (!!in_nmi() == ((vcpu)->arch.handling_intr_from_guest == KVM_HANDLING_NMI)))
 
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 #define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem)
 #endif
 
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 538ed1e803326..2f8e1b5a8a72c 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -84,7 +84,7 @@ config KVM_SW_PROTECTED_VM
 	bool "Enable support for KVM software-protected VMs"
 	depends on EXPERT
 	depends on KVM_X86 && X86_64
-	select KVM_GENERIC_MEMORY_ATTRIBUTES
+	select KVM_VM_MEMORY_ATTRIBUTES
 	help
 	  Enable support for KVM software-protected VMs.  Currently, software-
 	  protected VMs are purely a development and testing vehicle for
@@ -135,7 +135,7 @@ config KVM_INTEL_TDX
 	bool "Intel Trust Domain Extensions (TDX) support"
 	default y
 	depends on INTEL_TDX_HOST
-	select KVM_GENERIC_MEMORY_ATTRIBUTES
+	select KVM_VM_MEMORY_ATTRIBUTES
 	select HAVE_KVM_ARCH_GMEM_POPULATE
 	help
 	  Provides support for launching Intel Trust Domain Extensions (TDX)
@@ -159,7 +159,7 @@ config KVM_AMD_SEV
 	depends on KVM_AMD && X86_64
 	depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
 	select ARCH_HAS_CC_PLATFORM
-	select KVM_GENERIC_MEMORY_ATTRIBUTES
+	select KVM_VM_MEMORY_ATTRIBUTES
 	select HAVE_KVM_ARCH_GMEM_CONVERT
 	select HAVE_KVM_ARCH_GMEM_RECLAIM
 	select HAVE_KVM_ARCH_GMEM_INVALIDATE
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index c519e8e8d646f..acafa7964964c 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -8070,7 +8070,7 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
 		vhost_task_stop(kvm->arch.nx_huge_page_recovery_thread);
 }
 
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 static bool hugepage_test_mixed(struct kvm_memory_slot *slot, gfn_t gfn,
 				int level)
 {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0f1a829032c06..3308d58342955 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10126,7 +10126,7 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm,
 		}
 	}
 
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	kvm_mmu_init_memslot_memory_attributes(kvm, slot);
 #endif
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 6aab167bf4823..9f78a466c6f3e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -722,7 +722,7 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
 }
 #endif
 
-#ifndef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifndef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 static inline bool kvm_arch_has_private_mem(struct kvm *kvm)
 {
 	return false;
@@ -871,7 +871,7 @@ struct kvm {
 #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
 	struct notifier_block pm_notifier;
 #endif
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	/* Protected by slots_lock (for writes) and RCU (for reads) */
 	struct xarray mem_attr_array;
 #endif
@@ -2559,7 +2559,7 @@ static inline bool kvm_memslot_is_gmem_only(const struct kvm_memory_slot *slot)
 	return slot->flags & KVM_MEMSLOT_GMEM_ONLY;
 }
 
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn)
 {
 	return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
@@ -2581,7 +2581,7 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 {
 	return false;
 }
-#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
+#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
 #ifdef CONFIG_KVM_GUEST_MEMFD
 int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h
index b282e3a867696..1ba72bd73ea2f 100644
--- a/include/trace/events/kvm.h
+++ b/include/trace/events/kvm.h
@@ -358,7 +358,7 @@ TRACE_EVENT(kvm_dirty_ring_exit,
 	TP_printk("vcpu %d", __entry->vcpu_id)
 );
 
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 /*
  * @start:	Starting address of guest memory range
  * @end:	End address of guest memory range
@@ -383,7 +383,7 @@ TRACE_EVENT(kvm_vm_set_mem_attributes,
 	TP_printk("%#016llx -- %#016llx [0x%lx]",
 		  __entry->start, __entry->end, __entry->attr)
 );
-#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
+#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
 TRACE_EVENT(kvm_unmap_hva_range,
 	TP_PROTO(unsigned long start, unsigned long end),
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index c3c0ee253fc77..df575449d97b5 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -100,7 +100,7 @@ config KVM_ELIDE_TLB_FLUSH_IF_YOUNG
 config KVM_MMU_LOCKLESS_AGING
        bool
 
-config KVM_GENERIC_MEMORY_ATTRIBUTES
+config KVM_VM_MEMORY_ATTRIBUTES
        bool
 
 config KVM_GUEST_MEMFD
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e9e32686e41be..902aa166c9c0c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1115,7 +1115,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
 	spin_lock_init(&kvm->mn_invalidate_lock);
 	rcuwait_init(&kvm->mn_memslots_update_rcuwait);
 	xa_init(&kvm->vcpu_array);
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	xa_init(&kvm->mem_attr_array);
 #endif
 
@@ -1300,7 +1300,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
 	cleanup_srcu_struct(&kvm->irq_srcu);
 	srcu_barrier(&kvm->srcu);
 	cleanup_srcu_struct(&kvm->srcu);
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	xa_destroy(&kvm->mem_attr_array);
 #endif
 	kvm_arch_free_vm(kvm);
@@ -2418,7 +2418,7 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
 }
 #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
 
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 static u64 kvm_supported_mem_attributes(struct kvm *kvm)
 {
 	if (!kvm || kvm_arch_has_private_mem(kvm))
@@ -2623,7 +2623,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 
 	return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes);
 }
-#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
+#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
 {
@@ -4933,7 +4933,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 	case KVM_CAP_SYSTEM_EVENT_DATA:
 	case KVM_CAP_DEVICE_CTRL:
 		return 1;
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	case KVM_CAP_MEMORY_ATTRIBUTES:
 		return kvm_supported_mem_attributes(kvm);
 #endif
@@ -5337,7 +5337,7 @@ static long kvm_vm_ioctl(struct file *filp,
 		break;
 	}
 #endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	case KVM_SET_MEMORY_ATTRIBUTES: {
 		struct kvm_memory_attributes attrs;
 
@@ -5348,7 +5348,7 @@ static long kvm_vm_ioctl(struct file *filp,
 		r = kvm_vm_ioctl_set_mem_attributes(kvm, &attrs);
 		break;
 	}
-#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
+#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 	case KVM_CREATE_DEVICE: {
 		struct kvm_create_device cd;
 

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 03/41] KVM: Enumerate support for PRIVATE memory iff kvm_arch_has_private_mem is defined

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Explicitly guard reporting support for KVM_MEMORY_ATTRIBUTE_PRIVATE based
on kvm_arch_has_private_mem being #defined in anticipation of decoupling
kvm_supported_mem_attributes() from CONFIG_KVM_VM_MEMORY_ATTRIBUTES.
guest_memfd support for memory attributes will be unconditional to avoid
yet more macros (all architectures that support guest_memfd are expected to
use per-gmem attributes at some point), at which point enumerating support
KVM_MEMORY_ATTRIBUTE_PRIVATE based solely on memory attributes being
supported _somewhere_ would result in KVM over-reporting support on arm64.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 include/linux/kvm_host.h | 2 +-
 virt/kvm/kvm_main.c      | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 9f78a466c6f3e..c125d2e8155a7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -722,7 +722,7 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
 }
 #endif
 
-#ifndef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+#ifndef kvm_arch_has_private_mem
 static inline bool kvm_arch_has_private_mem(struct kvm *kvm)
 {
 	return false;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 902aa166c9c0c..9501dd8d015d1 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2421,8 +2421,10 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
 #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 static u64 kvm_supported_mem_attributes(struct kvm *kvm)
 {
+#ifdef kvm_arch_has_private_mem
 	if (!kvm || kvm_arch_has_private_mem(kvm))
 		return KVM_MEMORY_ATTRIBUTE_PRIVATE;
+#endif
 
 	return 0;
 }

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 04/41] KVM: Rename memory attribute APIs to prepare for in-place gmem conversion

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Rename memory attribute APIs to add a "vm_" in the name in anticipation of
moving PRIVATE tracking into guest_memfd, to allow in-place conversion
between SHARED and PRIVATE.  At that point, there will effectively be two
(potential) sources of memory attributes: the VM and guest_memfd.

kvm_vm_set_mem_attributes() already has "vm" in the name to indicate that
it is a VM ioctl. Rename it to kvm_set_vm_mem_attributes() to show that it
is setting the VM's memory attributes. (Drop the VM-ioctl scoping since it
is a helper local to the file.) Update the accompanying trace function to
match.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 arch/x86/kvm/mmu/mmu.c     | 14 +++++++-------
 include/linux/kvm_host.h   | 16 ++++++++--------
 include/trace/events/kvm.h |  2 +-
 virt/kvm/guest_memfd.c     |  6 +++---
 virt/kvm/kvm_main.c        | 32 ++++++++++++++++----------------
 5 files changed, 35 insertions(+), 35 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index acafa7964964c..2b3bc73845a8a 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -8089,8 +8089,8 @@ static void hugepage_set_mixed(struct kvm_memory_slot *slot, gfn_t gfn,
 	lpage_info_slot(gfn, slot, level)->disallow_lpage |= KVM_LPAGE_MIXED_FLAG;
 }
 
-bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
-					struct kvm_gfn_range *range)
+bool kvm_arch_pre_set_vm_memory_attributes(struct kvm *kvm,
+					   struct kvm_gfn_range *range)
 {
 	struct kvm_memory_slot *slot = range->slot;
 	int level;
@@ -8159,18 +8159,18 @@ static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot,
 	const unsigned long end = start + KVM_PAGES_PER_HPAGE(level);
 
 	if (level == PG_LEVEL_2M)
-		return kvm_range_has_memory_attributes(kvm, start, end, ~0, attrs);
+		return kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attrs);
 
 	for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) {
 		if (hugepage_test_mixed(slot, gfn, level - 1) ||
-		    attrs != kvm_get_memory_attributes(kvm, gfn))
+		    attrs != kvm_get_vm_memory_attributes(kvm, gfn))
 			return false;
 	}
 	return true;
 }
 
-bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
-					 struct kvm_gfn_range *range)
+bool kvm_arch_post_set_vm_memory_attributes(struct kvm *kvm,
+					    struct kvm_gfn_range *range)
 {
 	unsigned long attrs = range->arg.attributes;
 	struct kvm_memory_slot *slot = range->slot;
@@ -8263,7 +8263,7 @@ void kvm_mmu_init_memslot_memory_attributes(struct kvm *kvm,
 		 * be manually checked as the attributes may already be mixed.
 		 */
 		for (gfn = start; gfn < end; gfn += nr_pages) {
-			unsigned long attrs = kvm_get_memory_attributes(kvm, gfn);
+			unsigned long attrs = kvm_get_vm_memory_attributes(kvm, gfn);
 
 			if (hugepage_has_attrs(kvm, slot, gfn, level, attrs))
 				hugepage_clear_mixed(slot, gfn, level);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c125d2e8155a7..297cb06302223 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2560,21 +2560,21 @@ static inline bool kvm_memslot_is_gmem_only(const struct kvm_memory_slot *slot)
 }
 
 #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
-static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn)
+static inline unsigned long kvm_get_vm_memory_attributes(struct kvm *kvm, gfn_t gfn)
 {
 	return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
 }
 
-bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
-				     unsigned long mask, unsigned long attrs);
-bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
-					struct kvm_gfn_range *range);
-bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
-					 struct kvm_gfn_range *range);
+bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
+					unsigned long mask, unsigned long attrs);
+bool kvm_arch_pre_set_vm_memory_attributes(struct kvm *kvm,
+					   struct kvm_gfn_range *range);
+bool kvm_arch_post_set_vm_memory_attributes(struct kvm *kvm,
+					    struct kvm_gfn_range *range);
 
 static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 {
-	return kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
+	return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
 }
 #else
 static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h
index 1ba72bd73ea2f..c4d514d2350cf 100644
--- a/include/trace/events/kvm.h
+++ b/include/trace/events/kvm.h
@@ -364,7 +364,7 @@ TRACE_EVENT(kvm_dirty_ring_exit,
  * @end:	End address of guest memory range
  * @attr:	The value of the attribute being set.
  */
-TRACE_EVENT(kvm_vm_set_mem_attributes,
+TRACE_EVENT(kvm_set_vm_mem_attributes,
 	TP_PROTO(gfn_t start, gfn_t end, unsigned long attr),
 	TP_ARGS(start, end, attr),
 
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 3d6547c5ba9a6..8c7709a352cc7 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -881,9 +881,9 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
 
 	folio_unlock(folio);
 
-	if (!kvm_range_has_memory_attributes(kvm, gfn, gfn + 1,
-					     KVM_MEMORY_ATTRIBUTE_PRIVATE,
-					     KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
+	if (!kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + 1,
+						KVM_MEMORY_ATTRIBUTE_PRIVATE,
+						KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
 		ret = -EINVAL;
 		goto out_put_folio;
 	}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 9501dd8d015d1..6f0bcab7a0ebc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2419,7 +2419,7 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
 #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
 
 #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
-static u64 kvm_supported_mem_attributes(struct kvm *kvm)
+static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm)
 {
 #ifdef kvm_arch_has_private_mem
 	if (!kvm || kvm_arch_has_private_mem(kvm))
@@ -2433,19 +2433,19 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm)
  * Returns true if _all_ gfns in the range [@start, @end) have attributes
  * such that the bits in @mask match @attrs.
  */
-bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
-				     unsigned long mask, unsigned long attrs)
+bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
+					unsigned long mask, unsigned long attrs)
 {
 	XA_STATE(xas, &kvm->mem_attr_array, start);
 	unsigned long index;
 	void *entry;
 
-	mask &= kvm_supported_mem_attributes(kvm);
+	mask &= kvm_supported_vm_mem_attributes(kvm);
 	if (attrs & ~mask)
 		return false;
 
 	if (end == start + 1)
-		return (kvm_get_memory_attributes(kvm, start) & mask) == attrs;
+		return (kvm_get_vm_memory_attributes(kvm, start) & mask) == attrs;
 
 	guard(rcu)();
 	if (!attrs)
@@ -2516,8 +2516,8 @@ static __always_inline void kvm_handle_gfn_range(struct kvm *kvm,
 		KVM_MMU_UNLOCK(kvm);
 }
 
-static bool kvm_pre_set_memory_attributes(struct kvm *kvm,
-					  struct kvm_gfn_range *range)
+static bool kvm_pre_set_vm_memory_attributes(struct kvm *kvm,
+					     struct kvm_gfn_range *range)
 {
 	/*
 	 * Unconditionally add the range to the invalidation set, regardless of
@@ -2532,18 +2532,18 @@ static bool kvm_pre_set_memory_attributes(struct kvm *kvm,
 	 */
 	kvm_mmu_invalidate_range_add(kvm, range->start, range->end);
 
-	return kvm_arch_pre_set_memory_attributes(kvm, range);
+	return kvm_arch_pre_set_vm_memory_attributes(kvm, range);
 }
 
 /* Set @attributes for the gfn range [@start, @end). */
-static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
+static int kvm_set_vm_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 				     unsigned long attributes)
 {
 	struct kvm_mmu_notifier_range pre_set_range = {
 		.start = start,
 		.end = end,
 		.arg.attributes = attributes,
-		.handler = kvm_pre_set_memory_attributes,
+		.handler = kvm_pre_set_vm_memory_attributes,
 		.on_lock = kvm_mmu_invalidate_start,
 		.flush_on_ret = true,
 		.may_block = true,
@@ -2552,7 +2552,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 		.start = start,
 		.end = end,
 		.arg.attributes = attributes,
-		.handler = kvm_arch_post_set_memory_attributes,
+		.handler = kvm_arch_post_set_vm_memory_attributes,
 		.on_lock = kvm_mmu_invalidate_end,
 		.may_block = true,
 	};
@@ -2562,12 +2562,12 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 
 	entry = attributes ? xa_mk_value(attributes) : NULL;
 
-	trace_kvm_vm_set_mem_attributes(start, end, attributes);
+	trace_kvm_set_vm_mem_attributes(start, end, attributes);
 
 	mutex_lock(&kvm->slots_lock);
 
 	/* Nothing to do if the entire range has the desired attributes. */
-	if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes))
+	if (kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attributes))
 		goto out_unlock;
 
 	/*
@@ -2606,7 +2606,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 	/* flags is currently not used. */
 	if (attrs->flags)
 		return -EINVAL;
-	if (attrs->attributes & ~kvm_supported_mem_attributes(kvm))
+	if (attrs->attributes & ~kvm_supported_vm_mem_attributes(kvm))
 		return -EINVAL;
 	if (attrs->size == 0 || attrs->address + attrs->size < attrs->address)
 		return -EINVAL;
@@ -2623,7 +2623,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 	 */
 	BUILD_BUG_ON(sizeof(attrs->attributes) != sizeof(unsigned long));
 
-	return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes);
+	return kvm_set_vm_mem_attributes(kvm, start, end, attrs->attributes);
 }
 #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
@@ -4937,7 +4937,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 		return 1;
 #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	case KVM_CAP_MEMORY_ATTRIBUTES:
-		return kvm_supported_mem_attributes(kvm);
+		return kvm_supported_vm_mem_attributes(kvm);
 #endif
 #ifdef CONFIG_KVM_GUEST_MEMFD
 	case KVM_CAP_GUEST_MEMFD:

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 05/41] KVM: Provide generic interface for checking memory private/shared status

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Introduce a generic kvm_mem_is_private() interface using a static call to
determine if a GFN is private. This allows the implementation for checking
a GFN's private/shared status to be set at runtime.

In preparation for choosing implementations between a guest_memfd lookup
and the existing VM attribute lookup, rename the existing
VM-attribute-based check to kvm_vm_mem_is_private to emphasize that it
looks up VM attributes.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 include/linux/kvm_host.h | 14 ++++++++++++--
 virt/kvm/kvm_main.c      | 15 +++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 297cb06302223..438567e3fa6a1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2572,16 +2572,26 @@ bool kvm_arch_pre_set_vm_memory_attributes(struct kvm *kvm,
 bool kvm_arch_post_set_vm_memory_attributes(struct kvm *kvm,
 					    struct kvm_gfn_range *range);
 
-static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
+static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 {
 	return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
 }
+#endif  /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
+
+#ifdef kvm_arch_has_private_mem
+typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn);
+DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t);
+
+static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
+{
+	return static_call(__kvm_mem_is_private)(kvm, gfn);
+}
 #else
 static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 {
 	return false;
 }
-#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
+#endif /* kvm_arch_has_private_mem */
 
 #ifdef CONFIG_KVM_GUEST_MEMFD
 int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6f0bcab7a0ebc..80317d2c15d07 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2627,6 +2627,20 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
 }
 #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
+#ifdef kvm_arch_has_private_mem
+DEFINE_STATIC_CALL_RET0(__kvm_mem_is_private, kvm_mem_is_private_t);
+EXPORT_STATIC_CALL_GPL(__kvm_mem_is_private);
+
+static void kvm_init_memory_attributes(void)
+{
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+	static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
+#endif
+}
+#else
+static void kvm_init_memory_attributes(void) { }
+#endif
+
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
 {
 	return __gfn_to_memslot(kvm_memslots(kvm), gfn);
@@ -6539,6 +6553,7 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
 	kvm_preempt_ops.sched_in = kvm_sched_in;
 	kvm_preempt_ops.sched_out = kvm_sched_out;
 
+	kvm_init_memory_attributes();
 	kvm_init_debug();
 
 	r = kvm_vfio_ops_init();

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 06/41] KVM: guest_memfd: Introduce function to check GFN private/shared status

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Introduce a function for KVM to check the private/shared status of guest
memory at a given GFN.

This will be used in a later patch.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 include/linux/kvm_host.h |  2 ++
 virt/kvm/guest_memfd.c   | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 438567e3fa6a1..73f564b87a324 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2594,6 +2594,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 #endif /* kvm_arch_has_private_mem */
 
 #ifdef CONFIG_KVM_GUEST_MEMFD
+bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn);
+
 int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 		     gfn_t gfn, kvm_pfn_t *pfn, struct page **page,
 		     int *max_order);
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 8c7709a352cc7..33c9830190e2e 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -474,6 +474,38 @@ static int kvm_gmem_mmap(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
+bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn)
+{
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+	struct inode *inode;
+
+	/*
+	 * guest_memfd is the only provider of private memory and
+	 * guest_memfd must be used with a memslot, hence if there's
+	 * no associated memslot, there's no chance of this gfn being
+	 * private.
+	 */
+	if (!slot)
+		return 0;
+
+	CLASS(gmem_get_file, file)(slot);
+	if (!file)
+		return 0;
+
+	inode = file_inode(file);
+
+	/*
+	 * Rely on the maple tree's internal RCU lock to ensure a
+	 * stable result. This result can become stale as soon as the
+	 * lock is dropped, so the caller _must_ still protect
+	 * consumption of private vs. shared by checking
+	 * mmu_invalidate_retry_gfn() under mmu_lock to serialize
+	 * against ongoing attribute updates.
+	 */
+	return kvm_gmem_is_private_mem(inode, kvm_gmem_get_index(slot, gfn));
+}
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_is_private);
+
 static struct file_operations kvm_gmem_fops = {
 	.mmap		= kvm_gmem_mmap,
 	.open		= generic_file_open,

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 07/41] KVM: guest_memfd: Wire up core private/shared attribute interfaces

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

With in-place conversion, guest_memfd is able to track the private/shared
status of memory. Use a global flag to toggle between tracking
private/shared status per-vm or within guest_memfd.

When queried for supported vm memory attributes, return 0 if attributes are
tracked in guest_memfd.

When querying for memory attributes over a range, look up memory attributes
based on the flag's state at query time.

For per-GFN memory attribute queries, choose an implementation (VM or
guest_memfd lookup) at KVM load time.

The flag is always false for now and will be made toggle-able after all
in-place conversion features are added in subsequent patches.

If/since the flag is false, if CONFIG_KVM_VM_MEMORY_ATTRIBUTES is also not
selected, the per-GFN memory attribute query defaults to returning
0 (false/not private).

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 include/linux/kvm_host.h |  4 ++++
 virt/kvm/guest_memfd.c   | 25 ++++++++++++++++++++++---
 virt/kvm/kvm_main.c      | 12 +++++++++++-
 3 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 73f564b87a324..a913dd57ae622 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2579,6 +2579,8 @@ static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 #endif  /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
 
 #ifdef kvm_arch_has_private_mem
+extern bool gmem_in_place_conversion;
+
 typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn);
 DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t);
 
@@ -2587,6 +2589,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 	return static_call(__kvm_mem_is_private)(kvm, gfn);
 }
 #else
+#define gmem_in_place_conversion false
+
 static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 {
 	return false;
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 33c9830190e2e..89cf922232920 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -893,6 +893,27 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn);
 
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
+static bool kvm_range_is_private(struct file *file, pgoff_t index,
+				 size_t nr_pages, struct kvm *kvm, gfn_t gfn)
+{
+	struct inode *inode = file_inode(file);
+	pgoff_t last = index + nr_pages - 1;
+	struct maple_tree *mt;
+	void *entry;
+
+	if (!gmem_in_place_conversion)
+		return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages,
+							  KVM_MEMORY_ATTRIBUTE_PRIVATE,
+							  KVM_MEMORY_ATTRIBUTE_PRIVATE);
+
+	mt = &GMEM_I(inode)->attributes;
+	mt_for_each(mt, entry, index, last) {
+		if (kvm_gmem_interpret_entry(inode, entry) !=
+		    KVM_MEMORY_ATTRIBUTE_PRIVATE)
+			return false;
+	}
+	return true;
+}
 
 static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
 				struct file *file, gfn_t gfn, struct page *src_page,
@@ -913,9 +934,7 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
 
 	folio_unlock(folio);
 
-	if (!kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + 1,
-						KVM_MEMORY_ATTRIBUTE_PRIVATE,
-						KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
+	if (!kvm_range_is_private(file, index, 1, kvm, gfn)) {
 		ret = -EINVAL;
 		goto out_put_folio;
 	}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 80317d2c15d07..0dfc91b9478ce 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -101,6 +101,10 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_shrink);
 static bool __ro_after_init allow_unsafe_mappings;
 module_param(allow_unsafe_mappings, bool, 0444);
 
+#ifdef kvm_arch_has_private_mem
+bool __ro_after_init gmem_in_place_conversion = false;
+#endif
+
 /*
  * Ordering of locks:
  *
@@ -2422,6 +2426,9 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
 static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm)
 {
 #ifdef kvm_arch_has_private_mem
+	if (gmem_in_place_conversion)
+		return 0;
+
 	if (!kvm || kvm_arch_has_private_mem(kvm))
 		return KVM_MEMORY_ATTRIBUTE_PRIVATE;
 #endif
@@ -2633,8 +2640,11 @@ EXPORT_STATIC_CALL_GPL(__kvm_mem_is_private);
 
 static void kvm_init_memory_attributes(void)
 {
+	if (gmem_in_place_conversion)
+		static_call_update(__kvm_mem_is_private, kvm_gmem_is_private);
 #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
-	static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
+	else
+		static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
 #endif
 }
 #else

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 08/41] KVM: Consolidate private memory and guest_memfd ifdeffery in kvm_host.h

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Move the kvm_arch_has_private_mem() stub and a few guest_memfd function
definitions/declarations "down" in kvm_host.h to utilize existing #ifdefs,
and so that related code is clustered together.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 include/linux/kvm_host.h | 37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a913dd57ae622..f408746d315f7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -722,27 +722,6 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
 }
 #endif
 
-#ifndef kvm_arch_has_private_mem
-static inline bool kvm_arch_has_private_mem(struct kvm *kvm)
-{
-	return false;
-}
-#endif
-
-#ifdef CONFIG_KVM_GUEST_MEMFD
-bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm);
-
-static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm)
-{
-	u64 flags = GUEST_MEMFD_FLAG_MMAP;
-
-	if (!kvm || kvm_arch_supports_gmem_init_shared(kvm))
-		flags |= GUEST_MEMFD_FLAG_INIT_SHARED;
-
-	return flags;
-}
-#endif
-
 #ifndef kvm_arch_has_readonly_mem
 static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm)
 {
@@ -2591,6 +2570,11 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 #else
 #define gmem_in_place_conversion false
 
+static inline bool kvm_arch_has_private_mem(struct kvm *kvm)
+{
+	return false;
+}
+
 static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 {
 	return false;
@@ -2599,6 +2583,17 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
 
 #ifdef CONFIG_KVM_GUEST_MEMFD
 bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn);
+bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm);
+
+static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm)
+{
+	u64 flags = GUEST_MEMFD_FLAG_MMAP;
+
+	if (!kvm || kvm_arch_supports_gmem_init_shared(kvm))
+		flags |= GUEST_MEMFD_FLAG_INIT_SHARED;
+
+	return flags;
+}
 
 int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 		     gfn_t gfn, kvm_pfn_t *pfn, struct page **page,

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 09/41] KVM: guest_memfd: Filter both shared and private when invalidating

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Before conversion, a guest_memfd could be either all shared, or all
private, configured at creation time using the INIT_SHARED flag. Hence,
when zapping pages from stage 2 page tables, guest_memfd can filter which
to zap based on the initial shared/private state.

With conversion, guest_memfd tracks shared/private state on a per-page
level, so a range can contain both private and shared pages. Zap both
private and shared pages for simplicity.

An alternative would be to iterate guest_memfd attributes and only zap both
if shared and private pages exist within the range. Setting both the shared
and private filters lets the zapping logic do that iteration instead.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 virt/kvm/guest_memfd.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 89cf922232920..6cbd96e2a99d3 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -135,14 +135,6 @@ static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index)
 	return folio;
 }
 
-static enum kvm_gfn_range_filter kvm_gmem_get_invalidate_filter(struct inode *inode)
-{
-	if (GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_INIT_SHARED)
-		return KVM_FILTER_SHARED;
-
-	return KVM_FILTER_PRIVATE;
-}
-
 static void __kvm_gmem_invalidate_start(struct gmem_file *f, pgoff_t start,
 					pgoff_t end,
 					enum kvm_gfn_range_filter attr_filter)
@@ -185,15 +177,13 @@ static void __kvm_gmem_invalidate_start(struct gmem_file *f, pgoff_t start,
 }
 
 static void kvm_gmem_invalidate_start(struct inode *inode, pgoff_t start,
-				      pgoff_t end)
+				      pgoff_t end,
+				      enum kvm_gfn_range_filter filter)
 {
-	enum kvm_gfn_range_filter attr_filter;
 	struct gmem_file *f;
 
-	attr_filter = kvm_gmem_get_invalidate_filter(inode);
-
 	kvm_gmem_for_each_file(f, inode)
-		__kvm_gmem_invalidate_start(f, start, end, attr_filter);
+		__kvm_gmem_invalidate_start(f, start, end, filter);
 }
 
 static void __kvm_gmem_invalidate_end(struct gmem_file *f, pgoff_t start,
@@ -228,7 +218,8 @@ static long kvm_gmem_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 	 */
 	filemap_invalidate_lock(inode->i_mapping);
 
-	kvm_gmem_invalidate_start(inode, start, end);
+	kvm_gmem_invalidate_start(inode, start, end,
+				  KVM_FILTER_SHARED | KVM_FILTER_PRIVATE);
 
 	truncate_inode_pages_range(inode->i_mapping, offset, offset + len - 1);
 
@@ -343,7 +334,7 @@ static int kvm_gmem_release(struct inode *inode, struct file *file)
 	 * memory, as its lifetime is associated with the inode, not the file.
 	 */
 	__kvm_gmem_invalidate_start(f, 0, -1ul,
-				    kvm_gmem_get_invalidate_filter(inode));
+				    KVM_FILTER_SHARED | KVM_FILTER_PRIVATE);
 	__kvm_gmem_invalidate_end(f, 0, -1ul);
 
 	list_del(&f->entry);
@@ -530,7 +521,8 @@ static int kvm_gmem_error_folio(struct address_space *mapping, struct folio *fol
 	start = folio->index;
 	end = start + folio_nr_pages(folio);
 
-	kvm_gmem_invalidate_start(mapping->host, start, end);
+	kvm_gmem_invalidate_start(mapping->host, start, end,
+				  KVM_FILTER_SHARED | KVM_FILTER_PRIVATE);
 
 	/*
 	 * Do not truncate the range, what action is taken in response to the

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 10/41] KVM: guest_memfd: Add base support for KVM_SET_MEMORY_ATTRIBUTES2

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add a new ioctl (and matching struct), KVM_SET_MEMORY_ATTRIBUTES2, using
the same base ioctl number (0xd2), but with R/W semantics for the kernel
instead of just read semantics.  "Officially" documenting that KVM writes
to the payload will allow KVM to support partial/incremental conversions,
instead of all-or-nothing updates (which requires complex unwinding), by
recording the failing offset if an error occurs.

Opportunistically add a new struct as well, even though KVM could squeeze
the error offset into "struct kvm_memory_attributes", as there's no cost to
doing so in practice.  Pad the struct with a pile of extra space to try and
avoid ending up with "struct kvm_memory_attributes3" in the future.  Use
the same layout for the fields that common to version 1 of the struct,
e.g. to ease upgrading userspace, and to provide flexibility if KVM ever
adds support for KVM_SET_MEMORY_ATTRIBUTES2 at VM scope.

Introduce KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES to advertise the
availability of the KVM_SET_MEMORY_ATTRIBUTES2 ioctl.

Update the KVM API documentation to define the new ioctl and its behavior,
and add the necessary UAPI definitions and capability checks.

The process of setting memory attributes has a clear point of no return
because, for CoCo VMs, zapping stage 2 page tables is a destructive
operation. Unlike regular VMs, where re-faulting pages into the stage 2
page tables merely incurs a performance penalty, CoCo guests must
(re-):accept pages after every fault. To preserve CoCo security guarantees,
guests will not accept pages they did not explicitly request faults
for. Consequently, during memory conversions, any operation that could
cause the process to abort must be completed before the stage 2 page tables
are zapped.

Zap only the ranges that are not already in the requested state to avoid
inadvertently destroying (CoCo) data. ARM CCA guests will try to mark the
entire DRAM as private at boot. If there are no shared pages at all, the
to-private conversion can be skipped, but the existence of a single shared
page would require the conversion process to proceed, and if it proceeds,
zapping both shared and private pages would destroy data and break the
guest.

Co-developed-by: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Suggested-by: Michael Roth <michael.roth@amd.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>

tmpo
---
 Documentation/virt/kvm/api.rst |  63 +++++++++++++++++++++-
 include/uapi/linux/kvm.h       |  15 ++++++
 virt/kvm/guest_memfd.c         | 119 +++++++++++++++++++++++++++++++++++++++++
 virt/kvm/kvm_main.c            |  23 +++++---
 4 files changed, 212 insertions(+), 8 deletions(-)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index a5f9ee92f43e8..de8ab3db8796a 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -117,7 +117,7 @@ description:
       x86 includes both i386 and x86_64.
 
   Type:
-      system, vm, or vcpu.
+      system, vm, vcpu or guest_memfd.
 
   Parameters:
       what parameters are accepted by the ioctl.
@@ -6373,6 +6373,8 @@ S390:
 Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set.
 Returns -EINVAL if called on a protected VM.
 
+.. _KVM_SET_MEMORY_ATTRIBUTES:
+
 4.141 KVM_SET_MEMORY_ATTRIBUTES
 -------------------------------
 
@@ -6566,6 +6568,65 @@ KVM_S390_KEYOP_SSKE
   Sets the storage key for the guest address ``guest_addr`` to the key
   specified in ``key``, returning the previous value in ``key``.
 
+4.145 KVM_SET_MEMORY_ATTRIBUTES2
+---------------------------------
+
+:Capability: KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES
+:Architectures: all
+:Type: guest_memfd ioctl
+:Parameters: struct kvm_memory_attributes2 (in)
+:Returns: 0 on success, <0 on error
+
+Errors:
+
+  ========== ===============================================================
+  EINVAL     The specified `offset` or `size` was invalid (e.g. not
+             page aligned, causes an overflow, or size is zero).
+  EFAULT     The parameter address was invalid.
+  ENOMEM     Ran out of memory trying to track private/shared state
+  ========== ===============================================================
+
+KVM_SET_MEMORY_ATTRIBUTES2 is an extension to
+KVM_SET_MEMORY_ATTRIBUTES that supports returning (writing) values to
+userspace.  The original (pre-extension) fields are shared with
+KVM_SET_MEMORY_ATTRIBUTES identically.
+
+Attribute values are shared with KVM_SET_MEMORY_ATTRIBUTES.
+
+::
+
+  struct kvm_memory_attributes2 {
+	union {
+		__u64 address;
+		__u64 offset;
+	};
+	__u64 size;
+	__u64 attributes;
+	__u64 flags;
+	__u64 reserved[12];
+  };
+
+  #define KVM_MEMORY_ATTRIBUTE_PRIVATE           (1ULL << 3)
+
+Set attributes for a range of offsets within a guest_memfd to
+KVM_MEMORY_ATTRIBUTE_PRIVATE to limit the specified guest_memfd backed
+memory range for guest use. Even if KVM_CAP_GUEST_MEMFD_MMAP is
+supported, after a successful call to set
+KVM_MEMORY_ATTRIBUTE_PRIVATE, the requested range will not be mappable
+into host userspace and will only be mappable by the guest.
+
+To allow the range to be mappable into host userspace again, call
+KVM_SET_MEMORY_ATTRIBUTES2 on the guest_memfd again with
+KVM_MEMORY_ATTRIBUTE_PRIVATE unset.
+
+KVM does not directly manipulate the memory contents of pages during
+attribute updates. However, the process of setting these attributes,
+which includes operations such as unmapping pages from the host or
+stage-2 page tables, may result in side effects on memory contents
+that vary across different trusted firmware implementations.
+
+See also: :ref: `KVM_SET_MEMORY_ATTRIBUTES`.
+
 .. _kvm_run:
 
 5. The kvm_run structure
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 419011097fa8e..80985e28e3b21 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -997,6 +997,7 @@ struct kvm_enable_cap {
 #define KVM_CAP_S390_KEYOP 247
 #define KVM_CAP_S390_VSIE_ESAMODE 248
 #define KVM_CAP_S390_HPAGE_2G 249
+#define KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES 250
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
@@ -1649,6 +1650,20 @@ struct kvm_memory_attributes {
 	__u64 flags;
 };
 
+/* Available with KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES */
+#define KVM_SET_MEMORY_ATTRIBUTES2              _IOWR(KVMIO,  0xd2, struct kvm_memory_attributes2)
+
+struct kvm_memory_attributes2 {
+	union {
+		__u64 address;
+		__u64 offset;
+	};
+	__u64 size;
+	__u64 attributes;
+	__u64 flags;
+	__u64 reserved[12];
+};
+
 #define KVM_MEMORY_ATTRIBUTE_PRIVATE           (1ULL << 3)
 
 #define KVM_CREATE_GUEST_MEMFD	_IOWR(KVMIO,  0xd4, struct kvm_create_guest_memfd)
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 6cbd96e2a99d3..c9b5151f010e9 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -497,11 +497,130 @@ bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_is_private);
 
+/*
+ * Preallocate memory for attributes to be stored on a maple tree, pointed to
+ * by mas.  Adjacent ranges with attributes identical to the new attributes
+ * will be merged.  Also sets mas's bounds up for storing attributes.
+ *
+ * This maintains the invariant that ranges with the same attributes will
+ * always be merged.
+ */
+static int kvm_gmem_mas_preallocate(struct ma_state *mas, u64 attributes,
+				    pgoff_t start, size_t nr_pages)
+{
+	pgoff_t end = start + nr_pages;
+	pgoff_t last = end - 1;
+	void *entry;
+
+	/* Try extending range. entry is NULL on overflow/wrap-around. */
+	mas_set(mas, end);
+	entry = mas_find(mas, end);
+	if (entry && xa_to_value(entry) == attributes)
+		last = mas->last;
+
+	if (start > 0) {
+		mas_set(mas, start - 1);
+		entry = mas_find(mas, start - 1);
+		if (entry && xa_to_value(entry) == attributes)
+			start = mas->index;
+	}
+
+	mas_set_range(mas, start, last);
+	return mas_preallocate(mas, xa_mk_value(attributes), GFP_KERNEL);
+}
+
+static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
+				     size_t nr_pages, uint64_t attrs)
+{
+	bool to_private = attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE;
+	struct address_space *mapping = inode->i_mapping;
+	struct gmem_inode *gi = GMEM_I(inode);
+	enum kvm_gfn_range_filter filter;
+	pgoff_t end = start + nr_pages;
+	struct maple_tree *mt;
+	struct ma_state mas;
+	int r;
+
+	mt = &gi->attributes;
+
+	filemap_invalidate_lock(mapping);
+
+	mas_init(&mas, mt, start);
+	r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages);
+	if (r)
+		goto out;
+
+	/*
+	 * From this point on guest_memfd has performed necessary
+	 * checks and can proceed to do guest-breaking changes.
+	 */
+
+	filter = to_private ? KVM_FILTER_SHARED : KVM_FILTER_PRIVATE;
+	kvm_gmem_invalidate_start(inode, start, end, filter);
+	mas_store_prealloc(&mas, xa_mk_value(attrs));
+	kvm_gmem_invalidate_end(inode, start, end);
+out:
+	filemap_invalidate_unlock(mapping);
+	return r;
+}
+
+static long kvm_gmem_set_attributes(struct file *file, void __user *argp)
+{
+	struct gmem_file *f = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct kvm_memory_attributes2 attrs;
+	size_t nr_pages;
+	pgoff_t index;
+	int i;
+
+	if (copy_from_user(&attrs, argp, sizeof(attrs)))
+		return -EFAULT;
+
+	if (attrs.flags)
+		return -EINVAL;
+	for (i = 0; i < ARRAY_SIZE(attrs.reserved); i++) {
+		if (attrs.reserved[i])
+			return -EINVAL;
+	}
+	if (!kvm_arch_has_private_mem(f->kvm))
+		return -EINVAL;
+	if (attrs.attributes & ~KVM_MEMORY_ATTRIBUTE_PRIVATE)
+		return -EINVAL;
+	if (attrs.size == 0 || attrs.offset + attrs.size < attrs.offset)
+		return -EINVAL;
+	if (!PAGE_ALIGNED(attrs.offset) || !PAGE_ALIGNED(attrs.size))
+		return -EINVAL;
+
+	if (attrs.offset >= i_size_read(inode) ||
+	    attrs.offset + attrs.size > i_size_read(inode))
+		return -EINVAL;
+
+	nr_pages = attrs.size >> PAGE_SHIFT;
+	index = attrs.offset >> PAGE_SHIFT;
+	return __kvm_gmem_set_attributes(inode, index, nr_pages,
+					 attrs.attributes);
+}
+
+static long kvm_gmem_ioctl(struct file *file, unsigned int ioctl,
+			   unsigned long arg)
+{
+	switch (ioctl) {
+	case KVM_SET_MEMORY_ATTRIBUTES2:
+		if (!gmem_in_place_conversion)
+			return -ENOTTY;
+
+		return kvm_gmem_set_attributes(file, (void __user *)arg);
+	default:
+		return -ENOTTY;
+	}
+}
+
 static struct file_operations kvm_gmem_fops = {
 	.mmap		= kvm_gmem_mmap,
 	.open		= generic_file_open,
 	.release	= kvm_gmem_release,
 	.fallocate	= kvm_gmem_fallocate,
+	.unlocked_ioctl	= kvm_gmem_ioctl,
 };
 
 static int kvm_gmem_migrate_folio(struct address_space *mapping,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0dfc91b9478ce..f0f802eaca16b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2422,18 +2422,22 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
 }
 #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
 
+#ifdef kvm_arch_has_private_mem
+static u64 kvm_supports_private_mem(struct kvm *kvm)
+{
+	return !kvm || kvm_arch_has_private_mem(kvm);
+}
+#else
+#define kvm_supports_private_mem(kvm) false
+#endif
+
 #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm)
 {
-#ifdef kvm_arch_has_private_mem
-	if (gmem_in_place_conversion)
+	if (gmem_in_place_conversion || !kvm_supports_private_mem(kvm))
 		return 0;
 
-	if (!kvm || kvm_arch_has_private_mem(kvm))
-		return KVM_MEMORY_ATTRIBUTE_PRIVATE;
-#endif
-
-	return 0;
+	return KVM_MEMORY_ATTRIBUTE_PRIVATE;
 }
 
 /*
@@ -4968,6 +4972,11 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 		return 1;
 	case KVM_CAP_GUEST_MEMFD_FLAGS:
 		return kvm_gmem_get_supported_flags(kvm);
+	case KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES:
+		if (!gmem_in_place_conversion || !kvm_supports_private_mem(kvm))
+			return 0;
+
+		return KVM_MEMORY_ATTRIBUTE_PRIVATE;
 #endif
 	default:
 		break;

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 11/41] KVM: guest_memfd: Ensure pages are not in use before conversion

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

When converting memory to private in guest_memfd, it is necessary to ensure
that the pages are not currently being accessed by any other part of the
kernel or userspace to avoid any current user writing to guest private
memory.

guest_memfd checks for unexpected refcounts to determine whether a page is
still in use. The only expected refcounts after unmapping the range
requested for conversion are those that are held by guest_memfd itself.

Update the kvm_memory_attributes2 structure to include an error_offset
field. This allows KVM to report the exact offset where a conversion
failed to userspace. If the safety check fails, return -EAGAIN and copy
the error_offset back to userspace so that it can potentially retry the
operation or handle the failure gracefully.

Update documentation to document the error_offset field and the possible
-EAGAIN error.

Suggested-by: David Hildenbrand <david@kernel.org>
Co-developed-by: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 Documentation/virt/kvm/api.rst | 19 ++++++++++--
 include/uapi/linux/kvm.h       |  3 +-
 virt/kvm/guest_memfd.c         | 67 ++++++++++++++++++++++++++++++++++++++----
 3 files changed, 81 insertions(+), 8 deletions(-)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index de8ab3db8796a..1de6fd5fc88c4 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -6574,7 +6574,7 @@ KVM_S390_KEYOP_SSKE
 :Capability: KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES
 :Architectures: all
 :Type: guest_memfd ioctl
-:Parameters: struct kvm_memory_attributes2 (in)
+:Parameters: struct kvm_memory_attributes2 (in/out)
 :Returns: 0 on success, <0 on error
 
 Errors:
@@ -6583,6 +6583,8 @@ Errors:
   EINVAL     The specified `offset` or `size` was invalid (e.g. not
              page aligned, causes an overflow, or size is zero).
   EFAULT     The parameter address was invalid.
+  EAGAIN     Some page within requested range had unexpected refcounts. The
+             offset of the page will be returned in `error_offset`.
   ENOMEM     Ran out of memory trying to track private/shared state
   ========== ===============================================================
 
@@ -6596,6 +6598,7 @@ Attribute values are shared with KVM_SET_MEMORY_ATTRIBUTES.
 ::
 
   struct kvm_memory_attributes2 {
+	/* in */
 	union {
 		__u64 address;
 		__u64 offset;
@@ -6603,7 +6606,9 @@ Attribute values are shared with KVM_SET_MEMORY_ATTRIBUTES.
 	__u64 size;
 	__u64 attributes;
 	__u64 flags;
-	__u64 reserved[12];
+	/* out */
+	__u64 error_offset;
+	__u64 reserved[11];
   };
 
   #define KVM_MEMORY_ATTRIBUTE_PRIVATE           (1ULL << 3)
@@ -6625,6 +6630,16 @@ which includes operations such as unmapping pages from the host or
 stage-2 page tables, may result in side effects on memory contents
 that vary across different trusted firmware implementations.
 
+If this ioctl returns -EAGAIN, the offset of the page with unexpected
+refcounts will be returned in `error_offset`. This can occur if there
+are transient refcounts on the pages, taken by other parts of the
+kernel.
+
+Userspace is expected to figure out how to remove all known refcounts
+on the shared pages, such as refcounts taken by get_user_pages(), and
+try the ioctl again. A possible source of these long term refcounts is
+if the guest_memfd memory was pinned in IOMMU page tables.
+
 See also: :ref: `KVM_SET_MEMORY_ATTRIBUTES`.
 
 .. _kvm_run:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 80985e28e3b21..129d6f6303251 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1661,7 +1661,8 @@ struct kvm_memory_attributes2 {
 	__u64 size;
 	__u64 attributes;
 	__u64 flags;
-	__u64 reserved[12];
+	__u64 error_offset;
+	__u64 reserved[11];
 };
 
 #define KVM_MEMORY_ATTRIBUTE_PRIVATE           (1ULL << 3)
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index c9b5151f010e9..d3c813dcbf96d 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -529,8 +529,43 @@ static int kvm_gmem_mas_preallocate(struct ma_state *mas, u64 attributes,
 	return mas_preallocate(mas, xa_mk_value(attributes), GFP_KERNEL);
 }
 
+static bool kvm_gmem_is_safe_for_conversion(struct inode *inode, pgoff_t start,
+					    size_t nr_pages, pgoff_t *err_index)
+{
+	struct address_space *mapping = inode->i_mapping;
+	const int filemap_get_folios_refcount = 1;
+	pgoff_t last = start + nr_pages - 1;
+	struct folio_batch fbatch;
+	bool safe = true;
+	pgoff_t next;
+	int i;
+
+	folio_batch_init(&fbatch);
+
+	next = start;
+	while (safe && filemap_get_folios(mapping, &next, last, &fbatch)) {
+
+		for (i = 0; i < folio_batch_count(&fbatch); ++i) {
+			struct folio *folio = fbatch.folios[i];
+
+			if (folio_ref_count(folio) !=
+			    folio_nr_pages(folio) + filemap_get_folios_refcount) {
+				safe = false;
+				*err_index = max(start, folio->index);
+				break;
+			}
+		}
+
+		folio_batch_release(&fbatch);
+		cond_resched();
+	}
+
+	return safe;
+}
+
 static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
-				     size_t nr_pages, uint64_t attrs)
+				     size_t nr_pages, uint64_t attrs,
+				     pgoff_t *err_index)
 {
 	bool to_private = attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE;
 	struct address_space *mapping = inode->i_mapping;
@@ -547,8 +582,21 @@ static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
 
 	mas_init(&mas, mt, start);
 	r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages);
-	if (r)
+	if (r) {
+		*err_index = start;
 		goto out;
+	}
+
+	if (to_private) {
+		unmap_mapping_pages(mapping, start, nr_pages, false);
+
+		if (!kvm_gmem_is_safe_for_conversion(inode, start, nr_pages,
+						     err_index)) {
+			mas_destroy(&mas);
+			r = -EAGAIN;
+			goto out;
+		}
+	}
 
 	/*
 	 * From this point on guest_memfd has performed necessary
@@ -569,9 +617,10 @@ static long kvm_gmem_set_attributes(struct file *file, void __user *argp)
 	struct gmem_file *f = file->private_data;
 	struct inode *inode = file_inode(file);
 	struct kvm_memory_attributes2 attrs;
+	pgoff_t err_index;
 	size_t nr_pages;
 	pgoff_t index;
-	int i;
+	int i, r;
 
 	if (copy_from_user(&attrs, argp, sizeof(attrs)))
 		return -EFAULT;
@@ -597,8 +646,16 @@ static long kvm_gmem_set_attributes(struct file *file, void __user *argp)
 
 	nr_pages = attrs.size >> PAGE_SHIFT;
 	index = attrs.offset >> PAGE_SHIFT;
-	return __kvm_gmem_set_attributes(inode, index, nr_pages,
-					 attrs.attributes);
+	r = __kvm_gmem_set_attributes(inode, index, nr_pages, attrs.attributes,
+				      &err_index);
+	if (r) {
+		attrs.error_offset = ((uint64_t)err_index) << PAGE_SHIFT;
+
+		if (copy_to_user(argp, &attrs, sizeof(attrs)))
+			return -EFAULT;
+	}
+
+	return r;
 }
 
 static long kvm_gmem_ioctl(struct file *file, unsigned int ioctl,

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 12/41] KVM: guest_memfd: Call arch make_shared callback for to-shared conversion

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

When memory in guest_memfd is converted from private to shared, the
platform-specific state associated with the guest-private pages must be
invalidated or cleaned up.

Iterate over the folios in the affected range and call the
kvm_arch_gmem_invalidate() hook for each PFN range. This allows
architectures to perform necessary teardown, such as updating hardware
metadata or encryption states, before the pages are transitioned to the
shared state.

Invoke this helper after indicating to KVM's mmu code that an invalidation
is in progress to stop in-flight page faults from succeeding.

Omit support for calling the arch hook to make private, since SNP, the only
implementer of the arch make-private hook today, would actually prefer
making private only just before faulting memory into the NPTs.

Calling the make-private arch hook would require iterating both bindings
and the filemap to find the intersection of bindings and allocated
folios. On top of that, SNP would need to figure out whether to actually
make private based on whether the memory is about the be faulted, or
whether it is a conversion.

This does leak SNP-specific details into guest_memfd (as in, why only
make-shared during conversions but not make-private?), but the additional
complexity is not worth taking on until guest_memfd has a user actually
requiring an arch make-private call.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 arch/x86/include/asm/kvm-x86-ops.h |  2 +-
 arch/x86/include/asm/kvm_host.h    |  2 +-
 arch/x86/kvm/x86.c                 |  5 +++++
 include/linux/kvm_host.h           |  1 +
 virt/kvm/guest_memfd.c             | 42 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 5cb132eca3c35..8e0d6970c43b5 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -149,7 +149,7 @@ KVM_X86_OP_OPTIONAL(alloc_apic_backing_page)
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT
 KVM_X86_OP_OPTIONAL_RET0(gmem_make_private)
 #endif
-#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_RECLAIM
+#if defined(CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT) || defined(CONFIG_HAVE_KVM_ARCH_GMEM_RECLAIM)
 KVM_X86_OP_OPTIONAL(gmem_make_shared)
 #endif
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9fdf13b071097..ceb2abf43b76f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1730,7 +1730,7 @@ struct kvm_x86_ops {
 	int (*gmem_make_private)(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
 				 kvm_pfn_t nr_pages);
 #endif
-#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_RECLAIM
+#if defined(CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT) || defined(CONFIG_HAVE_KVM_ARCH_GMEM_RECLAIM)
 	void (*gmem_make_shared)(kvm_pfn_t pfn, kvm_pfn_t nr_pages);
 #endif
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3308d58342955..52de3ec7c7f73 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10639,6 +10639,11 @@ int kvm_arch_gmem_make_private(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
 {
 	return kvm_x86_call(gmem_make_private)(kvm, gfn, pfn, nr_pages);
 }
+
+void kvm_arch_gmem_make_shared(kvm_pfn_t pfn, kvm_pfn_t nr_pages)
+{
+	kvm_x86_call(gmem_make_shared)(pfn, nr_pages);
+}
 #endif
 
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_RECLAIM
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f408746d315f7..47f633cddffe0 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2612,6 +2612,7 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm,
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT
 int kvm_arch_gmem_make_private(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
 			       kvm_pfn_t nr_pages);
+void kvm_arch_gmem_make_shared(kvm_pfn_t pfn, kvm_pfn_t nr_pages);
 #endif
 
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index d3c813dcbf96d..612fcde4ae8ea 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -563,6 +563,43 @@ static bool kvm_gmem_is_safe_for_conversion(struct inode *inode, pgoff_t start,
 	return safe;
 }
 
+#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT
+static void kvm_gmem_make_shared(struct inode *inode, pgoff_t start, pgoff_t end)
+{
+	struct folio_batch fbatch;
+	pgoff_t next = start;
+	int i;
+
+	folio_batch_init(&fbatch);
+	while (filemap_get_folios(inode->i_mapping, &next, end - 1, &fbatch)) {
+		for (i = 0; i < folio_batch_count(&fbatch); ++i) {
+			struct folio *folio = fbatch.folios[i];
+			pgoff_t start_index, end_index;
+			kvm_pfn_t start_pfn;
+			kvm_pfn_t nr_pages;
+
+			start_index = max(start, folio->index);
+			end_index = min(end, folio_next_index(folio));
+			/*
+			 * end_index is either in folio or points to
+			 * the first page of the next folio. Hence,
+			 * all pages in range [start_index, end_index)
+			 * are contiguous.
+			 */
+			start_pfn = folio_file_pfn(folio, start_index);
+			nr_pages = end_index - start_index;
+
+			kvm_arch_gmem_make_shared(start_pfn, nr_pages);
+		}
+
+		folio_batch_release(&fbatch);
+		cond_resched();
+	}
+}
+#else
+static void kvm_gmem_make_shared(struct inode *inode, pgoff_t start, pgoff_t end) {}
+#endif
+
 static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
 				     size_t nr_pages, uint64_t attrs,
 				     pgoff_t *err_index)
@@ -605,7 +642,12 @@ static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
 
 	filter = to_private ? KVM_FILTER_SHARED : KVM_FILTER_PRIVATE;
 	kvm_gmem_invalidate_start(inode, start, end, filter);
+
+	if (!to_private)
+		kvm_gmem_make_shared(inode, start, end);
+
 	mas_store_prealloc(&mas, xa_mk_value(attrs));
+
 	kvm_gmem_invalidate_end(inode, start, end);
 out:
 	filemap_invalidate_unlock(mapping);

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 13/41] KVM: guest_memfd: Return early if range already has requested attributes

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Extract a helper out of kvm_gmem_range_is_private() that checks that a
range has given attributes.

Optimize setting memory attributes by returning early if all pages in the
requested range already has the requested attributes.

Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 virt/kvm/guest_memfd.c | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 612fcde4ae8ea..928fc7f4a01e4 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -94,6 +94,24 @@ static bool kvm_gmem_is_shared_mem(struct inode *inode, pgoff_t index)
 	return !kvm_gmem_is_private_mem(inode, index);
 }
 
+static bool kvm_gmem_range_has_attributes(struct inode *inode,
+					  pgoff_t index, size_t nr_pages,
+					  u64 attributes)
+{
+	struct maple_tree *mt = &GMEM_I(inode)->attributes;
+	pgoff_t end = index + nr_pages - 1;
+	void *entry;
+
+	lockdep_assert(mt_lock_is_held(mt));
+
+	mt_for_each(mt, entry, index, end) {
+		if (kvm_gmem_interpret_entry(inode, entry) != attributes)
+			return false;
+	}
+
+	return true;
+}
+
 /*
  * Returns a locked folio on success.  The caller is responsible for
  * setting the up-to-date flag before the memory is mapped into the guest.
@@ -611,12 +629,15 @@ static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
 	pgoff_t end = start + nr_pages;
 	struct maple_tree *mt;
 	struct ma_state mas;
-	int r;
+	int r = 0;
 
 	mt = &gi->attributes;
 
 	filemap_invalidate_lock(mapping);
 
+	if (kvm_gmem_range_has_attributes(inode, start, nr_pages, attrs))
+		goto out;
+
 	mas_init(&mas, mt, start);
 	r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages);
 	if (r) {
@@ -1107,22 +1128,14 @@ static bool kvm_range_is_private(struct file *file, pgoff_t index,
 				 size_t nr_pages, struct kvm *kvm, gfn_t gfn)
 {
 	struct inode *inode = file_inode(file);
-	pgoff_t last = index + nr_pages - 1;
-	struct maple_tree *mt;
-	void *entry;
 
 	if (!gmem_in_place_conversion)
 		return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages,
 							  KVM_MEMORY_ATTRIBUTE_PRIVATE,
 							  KVM_MEMORY_ATTRIBUTE_PRIVATE);
 
-	mt = &GMEM_I(inode)->attributes;
-	mt_for_each(mt, entry, index, last) {
-		if (kvm_gmem_interpret_entry(inode, entry) !=
-		    KVM_MEMORY_ATTRIBUTE_PRIVATE)
-			return false;
-	}
-	return true;
+	return kvm_gmem_range_has_attributes(inode, index, nr_pages,
+					     KVM_MEMORY_ATTRIBUTE_PRIVATE);
 }
 
 static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 14/41] mm: swap: Introduce lru_add_drain_progressive()

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Extract the progressive LRU drain retry logic from
collect_longterm_unpinnable_folios() into a reusable helper,
lru_add_drain_progressive().

When attempting to isolate folios that may still reside in per-CPU folio
batches, draining is escalated progressively:

1. State 0: Call lru_add_drain() to flush local CPU batches.
2. State 1: Call lru_add_drain_all() to flush all CPU batches.
3. State >= 2: Return false to stop retrying.

Refactor collect_longterm_unpinnable_folios() to use this new helper.

The helper will be used by KVM's guest_memfd in a later patch.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 include/linux/swap.h |  2 ++
 mm/gup.c             | 19 ++++++-------------
 mm/swap.c            | 15 +++++++++++++++
 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 8f0f68e245baa..cd54f73f34f39 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -344,6 +344,8 @@ extern void lru_add_drain(void);
 extern void lru_add_drain_cpu(int cpu);
 extern void lru_add_drain_cpu_zone(struct zone *zone);
 extern void lru_add_drain_all(void);
+bool lru_add_drain_progressive(int *drain_state);
+
 void folio_deactivate(struct folio *folio);
 void folio_mark_lazyfree(struct folio *folio);
 extern void swap_setup(void);
diff --git a/mm/gup.c b/mm/gup.c
index 0692119b79043..5f00435e2c635 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2268,7 +2268,7 @@ static unsigned long collect_longterm_unpinnable_folios(
 {
 	unsigned long collected = 0;
 	struct folio *folio;
-	int drained = 0;
+	int drain_state = 0;
 	long i = 0;
 
 	for (folio = pofs_get_folio(pofs, i); folio;
@@ -2287,18 +2287,11 @@ static unsigned long collect_longterm_unpinnable_folios(
 			continue;
 		}
 
-		if (drained == 0 && folio_may_be_lru_cached(folio) &&
-				folio_ref_count(folio) !=
-				folio_expected_ref_count(folio) + 1) {
-			lru_add_drain();
-			drained = 1;
-		}
-		if (drained == 1 && folio_may_be_lru_cached(folio) &&
-				folio_ref_count(folio) !=
-				folio_expected_ref_count(folio) + 1) {
-			lru_add_drain_all();
-			drained = 2;
-		}
+		while (folio_may_be_lru_cached(folio) &&
+		       folio_ref_count(folio) !=
+		       folio_expected_ref_count(folio) + 1 &&
+		       lru_add_drain_progressive(&drain_state))
+			;
 
 		if (!folio_isolate_lru(folio))
 			continue;
diff --git a/mm/swap.c b/mm/swap.c
index 588f50d8f1a8c..0f9465d31fe52 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -950,6 +950,21 @@ void lru_add_drain_all(void)
 }
 #endif /* CONFIG_SMP */
 
+bool lru_add_drain_progressive(int *drain_state)
+{
+	if (*drain_state == 0) {
+		lru_add_drain();
+		*drain_state = 1;
+		return true;
+	}
+	if (*drain_state == 1) {
+		lru_add_drain_all();
+		*drain_state = 2;
+		return true;
+	}
+	return false;
+}
+
 atomic_t lru_disable_count = ATOMIC_INIT(0);
 
 /*

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 15/41] KVM: guest_memfd: Handle lru_add fbatch refcounts during conversion safety check

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

When checking if a guest_memfd folio is safe for conversion, its refcount
is examined. A folio may be present in a per-CPU lru_add fbatch, which
temporarily increases its refcount. This can lead to a false positive,
incorrectly indicating that the folio is in use and preventing the
conversion, even if it is otherwise safe.

The conversion process might not be on the same CPU that holds the folio in
its fbatch. Hence, use lru_add_drain_progressive() to progressively drain
lru_add fbatches.

guest_memfd folios are unevictable, so they can only reside in the lru_add
fbatch. If the folio's refcount is still unsafe after draining, then the
conversion is truly unsafe and has to be aborted.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 mm/swap.c              |  2 ++
 virt/kvm/guest_memfd.c | 12 ++++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 0f9465d31fe52..4427d76c88d6d 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -37,6 +37,7 @@
 #include <linux/page_idle.h>
 #include <linux/local_lock.h>
 #include <linux/buffer_head.h>
+#include <linux/kvm_types.h>
 
 #include "internal.h"
 
@@ -964,6 +965,7 @@ bool lru_add_drain_progressive(int *drain_state)
 	}
 	return false;
 }
+EXPORT_SYMBOL_FOR_KVM(lru_add_drain_progressive);
 
 atomic_t lru_disable_count = ATOMIC_INIT(0);
 
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 928fc7f4a01e4..505bb6747620b 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -8,6 +8,7 @@
 #include <linux/mempolicy.h>
 #include <linux/pseudo_fs.h>
 #include <linux/pagemap.h>
+#include <linux/swap.h>
 
 #include "kvm_mm.h"
 
@@ -554,6 +555,7 @@ static bool kvm_gmem_is_safe_for_conversion(struct inode *inode, pgoff_t start,
 	const int filemap_get_folios_refcount = 1;
 	pgoff_t last = start + nr_pages - 1;
 	struct folio_batch fbatch;
+	int drain_state = 0;
 	bool safe = true;
 	pgoff_t next;
 	int i;
@@ -565,9 +567,15 @@ static bool kvm_gmem_is_safe_for_conversion(struct inode *inode, pgoff_t start,
 
 		for (i = 0; i < folio_batch_count(&fbatch); ++i) {
 			struct folio *folio = fbatch.folios[i];
+			int expected_refcount = folio_nr_pages(folio) +
+						filemap_get_folios_refcount;
 
-			if (folio_ref_count(folio) !=
-			    folio_nr_pages(folio) + filemap_get_folios_refcount) {
+			while (folio_may_be_lru_cached(folio) &&
+			       folio_ref_count(folio) != expected_refcount &&
+			       lru_add_drain_progressive(&drain_state))
+				;
+
+			if (folio_ref_count(folio) != expected_refcount) {
 				safe = false;
 				*err_index = max(start, folio->index);
 				break;

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 16/41] KVM: guest_memfd: Zero page while getting pfn

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Move the folio initialization logic from kvm_gmem_get_pfn() into
__kvm_gmem_get_pfn() to also zero pages if the page is to be used in
kvm_gmem_populate().

With in-place conversion, the existing data in a guest_memfd page can be
populated into guest memory through platform-specific ioctls.

Without first zeroing the page obtained using __kvm_gmem_get_pfn(), it
might contain uninitialized host memory, which would leak to the guest if
the populate completes.

guest_memfd pages are zeroed at most once in the page's entire lifetime
with guest_memfd, and that is tracked using the uptodate flag.

Zeroing the page in __kvm_gmem_get_pfn() is chosen over zeroing in
kvm_gmem_get_folio() since other flows, such as a future write() syscall,
can get a page, write to the page and then set page uptodate without
zeroing.

This aligns with the concept of zeroing before first use - the other place
where zeroing happens is in kvm_gmem_fault_user_mapping().

Don't mark the page uptodate again after populating, since the page would
already be marked uptodate before the post_populate() call.

Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 virt/kvm/guest_memfd.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 505bb6747620b..ea2752989f8bd 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -1078,6 +1078,11 @@ static struct folio *__kvm_gmem_get_pfn(struct file *file,
 		return ERR_PTR(-EHWPOISON);
 	}
 
+	if (!folio_test_uptodate(folio)) {
+		clear_highpage(folio_page(folio, 0));
+		folio_mark_uptodate(folio);
+	}
+
 	*pfn = folio_file_pfn(folio, index);
 	if (max_order)
 		*max_order = 0;
@@ -1107,11 +1112,6 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 		goto out;
 	}
 
-	if (!folio_test_uptodate(folio)) {
-		clear_highpage(folio_page(folio, 0));
-		folio_mark_uptodate(folio);
-	}
-
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT
 	if (kvm_gmem_is_private_mem(file_inode(file), index))
 		r = kvm_arch_gmem_make_private(kvm, gfn, *pfn,
@@ -1171,8 +1171,6 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
 	}
 
 	ret = post_populate(kvm, gfn, pfn, src_page, opaque);
-	if (!ret)
-		folio_mark_uptodate(folio);
 
 out_put_folio:
 	folio_put(folio);

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 17/41] KVM: SEV: Make 'uaddr' parameter optional for KVM_SEV_SNP_LAUNCH_UPDATE

[Ackerley Tng via B4 Relay]

From: Michael Roth <michael.roth@amd.com>

Make the source page for populating an SNP guest_memfd instance optional
if in-place conversion/population is enabled.  If KVM can convert the page
in-place, then it's possible for guest memory to be initialized directly
from userspace by mmap()'ing the guest_memfd and writing to it while the
corresponding GPA ranges are in a 'shared' state, before converting them
to the 'private' state expected by KVM_SEV_SNP_LAUNCH_UPDATE.

Update the handling/documentation for KVM_SEV_SNP_LAUNCH_UPDATE to allow
for 'uaddr' to be set to NULL when in-place conversion is enabled, which
SNP_LAUNCH_UPDATE will then use to determine when it should/shouldn't
copy in data from a separate memory location. Continue to enforce
non-NULL when PRIVATE is tracked per-VM, not per-guest_memfd.

Signed-off-by: Michael Roth <michael.roth@amd.com>
[Moved condition to snp_launch_update]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 Documentation/virt/kvm/x86/amd-memory-encryption.rst | 14 ++++++++++----
 arch/x86/kvm/svm/sev.c                               | 11 ++++++-----
 virt/kvm/kvm_main.c                                  |  1 +
 3 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
index bd04a908a8dbd..5977fbe33b98c 100644
--- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
@@ -503,7 +503,8 @@ secrets.
 
 It is required that the GPA ranges initialized by this command have had the
 KVM_MEMORY_ATTRIBUTE_PRIVATE attribute set in advance. See the documentation
-for KVM_SET_MEMORY_ATTRIBUTES for more details on this aspect.
+for KVM_SET_MEMORY_ATTRIBUTES/KVM_SET_MEMORY_ATTRIBUTES2 for more details on
+this aspect.
 
 Upon success, this command is not guaranteed to have processed the entire
 range requested. Instead, the ``gfn_start``, ``uaddr``, and ``len`` fields of
@@ -511,9 +512,14 @@ range requested. Instead, the ``gfn_start``, ``uaddr``, and ``len`` fields of
 remaining range that has yet to be processed. The caller should continue
 calling this command until those fields indicate the entire range has been
 processed, e.g. ``len`` is 0, ``gfn_start`` is equal to the last GFN in the
-range plus 1, and ``uaddr`` is the last byte of the userspace-provided source
-buffer address plus 1. In the case where ``type`` is KVM_SEV_SNP_PAGE_TYPE_ZERO,
-``uaddr`` will be ignored completely.
+range plus 1, and ``uaddr`` (if specified) is the last byte of the
+userspace-provided source buffer address plus 1.
+
+In the case where ``type`` is KVM_SEV_SNP_PAGE_TYPE_ZERO, ``uaddr`` will be
+ignored completely. For all other page types, ``uaddr`` is optional if in-place
+conversion is enabled (i.e. when the data had been written directly to
+guest_memfd while the page was in the shared state) and is required if in-place
+conversion is disabled.
 
 Parameters (in): struct  kvm_sev_snp_launch_update
 
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 90a08d36d843d..0f6fec21c1355 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2395,7 +2395,7 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
 	 */
 	if (ret && !snp_page_reclaim(kvm, pfn) &&
 	    sev_populate_args->type == KVM_SEV_SNP_PAGE_TYPE_CPUID &&
-	    sev_populate_args->fw_error == SEV_RET_INVALID_PARAM) {
+	    sev_populate_args->fw_error == SEV_RET_INVALID_PARAM && src_page) {
 		void *src_vaddr = kmap_local_page(src_page);
 		void *dst_vaddr = kmap_local_pfn(pfn);
 
@@ -2428,8 +2428,8 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	if (copy_from_user(&params, u64_to_user_ptr(argp->data), sizeof(params)))
 		return -EFAULT;
 
-	pr_debug("%s: GFN start 0x%llx length 0x%llx type %d flags %d\n", __func__,
-		 params.gfn_start, params.len, params.type, params.flags);
+	pr_debug("%s: GFN start 0x%llx length 0x%llx type %d flags %d src %llx\n", __func__,
+		 params.gfn_start, params.len, params.type, params.flags, params.uaddr);
 
 	if (!params.len || !PAGE_ALIGNED(params.len) || params.flags ||
 	    (params.type != KVM_SEV_SNP_PAGE_TYPE_NORMAL &&
@@ -2441,7 +2441,8 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 	if (params.type == KVM_SEV_SNP_PAGE_TYPE_ZERO)
 		src = NULL;
-	else if (!params.uaddr || !PAGE_ALIGNED(params.uaddr))
+	else if ((!gmem_in_place_conversion && !params.uaddr) ||
+		 !PAGE_ALIGNED(params.uaddr))
 		return -EINVAL;
 	else
 		src = u64_to_user_ptr(params.uaddr);
@@ -2488,7 +2489,7 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 	params.gfn_start += count;
 	params.len -= count * PAGE_SIZE;
-	if (params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO)
+	if (src && params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO)
 		params.uaddr += count * PAGE_SIZE;
 
 	if (copy_to_user(u64_to_user_ptr(argp->data), &params, sizeof(params)))
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f0f802eaca16b..e961cc297ba2a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -103,6 +103,7 @@ module_param(allow_unsafe_mappings, bool, 0444);
 
 #ifdef kvm_arch_has_private_mem
 bool __ro_after_init gmem_in_place_conversion = false;
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(gmem_in_place_conversion);
 #endif
 
 /*

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 18/41] KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Update tdx_gmem_post_populate() to handle cases where userspace requests
"no source page". To handle "no source page", populate (perform
TDH.MEM.PAGE.ADD) using memory in-place at the target PFN.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 Documentation/virt/kvm/x86/intel-tdx.rst | 4 ++++
 arch/x86/kvm/vmx/tdx.c                   | 8 +++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Documentation/virt/kvm/x86/intel-tdx.rst b/Documentation/virt/kvm/x86/intel-tdx.rst
index 6a222e9d09541..d8d9409120e61 100644
--- a/Documentation/virt/kvm/x86/intel-tdx.rst
+++ b/Documentation/virt/kvm/x86/intel-tdx.rst
@@ -158,6 +158,10 @@ KVM_TDX_INIT_MEM_REGION
 Initialize @nr_pages TDX guest private memory starting from @gpa with userspace
 provided data from @source_addr. @source_addr must be PAGE_SIZE-aligned.
 
+If guest_memfd in-place conversion is enabled, pass 0 for @source_addr
+to represent "no source page". A source page is required if in-place
+conversion is not enabled or not supported.
+
 Note, before calling this sub command, memory attribute of the range
 [gpa, gpa + nr_pages] needs to be private.  Userspace can use
 KVM_SET_MEMORY_ATTRIBUTES to set the attribute.
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index d1af0a752e97e..e890da5f18aed 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -3192,7 +3192,7 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
 	if (KVM_BUG_ON(kvm_tdx->page_add_src, kvm))
 		return -EIO;
 
-	kvm_tdx->page_add_src = src_page;
+	kvm_tdx->page_add_src = src_page ?: pfn_to_page(pfn);
 	ret = kvm_tdp_mmu_map_private_pfn(arg->vcpu, gfn, pfn);
 	kvm_tdx->page_add_src = NULL;
 
@@ -3238,7 +3238,8 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c
 	if (copy_from_user(&region, u64_to_user_ptr(cmd->data), sizeof(region)))
 		return -EFAULT;
 
-	if (!PAGE_ALIGNED(region.source_addr) || !region.source_addr ||
+	if (!PAGE_ALIGNED(region.source_addr) ||
+	    (!gmem_in_place_conversion && !region.source_addr) ||
 	    !PAGE_ALIGNED(region.gpa) || !region.nr_pages ||
 	    region.gpa + (region.nr_pages << PAGE_SHIFT) <= region.gpa ||
 	    !vt_is_tdx_private_gpa(kvm, region.gpa) ||
@@ -3269,7 +3270,8 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c
 			break;
 		}
 
-		region.source_addr += PAGE_SIZE;
+		if (region.source_addr)
+			region.source_addr += PAGE_SIZE;
 		region.gpa += PAGE_SIZE;
 		region.nr_pages--;
 

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 19/41] KVM: Move KVM_VM_MEMORY_ATTRIBUTES config definition to x86

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Bury KVM_VM_MEMORY_ATTRIBUTES in x86 to discourage other architectures
from adding support for per-VM memory attributes, because tracking private
vs. shared memory on a per-VM basis is now deprecated in favor of tracking
on a per-guest_memfd basis, and while RWX memory attributes are on the
horizon, they too are expected to be x86-only.

This will also allow modifying KVM_VM_MEMORY_ATTRIBUTES to be
user-selectable (in x86) without creating weirdness in KVM's Kconfigs.
Now that guest_memfd supports in-place conversions, it's entirely possible
to run x86 CoCo VMs without support for KVM_VM_MEMORY_ATTRIBUTES.

Leave the code itself in common KVM so that it's trivial to undo this
change if new per-VM attributes do come along.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 arch/x86/kvm/Kconfig | 3 +++
 virt/kvm/Kconfig     | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 2f8e1b5a8a72c..abb108886733a 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -80,6 +80,9 @@ config KVM_WERROR
 
 	  If in doubt, say "N".
 
+config KVM_VM_MEMORY_ATTRIBUTES
+	bool
+
 config KVM_SW_PROTECTED_VM
 	bool "Enable support for KVM software-protected VMs"
 	depends on EXPERT
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index df575449d97b5..a0678ef8ee3f5 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -100,9 +100,6 @@ config KVM_ELIDE_TLB_FLUSH_IF_YOUNG
 config KVM_MMU_LOCKLESS_AGING
        bool
 
-config KVM_VM_MEMORY_ATTRIBUTES
-       bool
-
 config KVM_GUEST_MEMFD
        select XARRAY_MULTI
        bool

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 20/41] KVM: Let userspace disable per-VM mem attributes, enable per-gmem attributes

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Make gmem_in_place_conversion a module parameter so that userspace can
configure enable or disable the use of VM-level memory attributes. The
module parameter is only available if CONFIG_KVM_VM_MEMORY_ATTRIBUTES is
enabled.

To avoid inconsistencies in the way memory attributes are tracked in KVM
and guest_memfd, the vm_memory_attributes module_param is made
read-only (0444).

Since selecting CONFIG_KVM_VM_MEMORY_ATTRIBUTES disables in-place
conversion, actually make CONFIG_KVM_VM_MEMORY_ATTRIBUTES selectable. Make
the config only selectable for (CoCo) VM types that might use
vm_memory_attributes.

Since memory attributes are trackable in guest_memfd, the concept of having
private memory is no longer dependent on
CONFIG_KVM_VM_MEMORY_ATTRIBUTES. Define kvm_arch_has_private_mem() based on
platform config, so that having private memory is dependent on (CoCo) VM
type.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
[Define module_param only if CONFIG_KVM_VM_MEMORY_ATTRIBUTES is enabled]
Suggested-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 arch/x86/include/asm/kvm_host.h |  4 +++-
 arch/x86/kvm/Kconfig            | 14 ++++++++++----
 virt/kvm/guest_memfd.c          |  2 ++
 virt/kvm/kvm_main.c             |  5 ++++-
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ceb2abf43b76f..766eb094eaae6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1849,7 +1849,9 @@ enum kvm_intr_type {
 	((vcpu) && (vcpu)->arch.handling_intr_from_guest && \
 	 (!!in_nmi() == ((vcpu)->arch.handling_intr_from_guest == KVM_HANDLING_NMI)))
 
-#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+#if defined(CONFIG_KVM_SW_PROTECTED_VM) ||	\
+    defined(CONFIG_KVM_INTEL_TDX) ||		\
+    defined(CONFIG_KVM_AMD_SEV)
 #define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem)
 #endif
 
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index abb108886733a..2c3c22aeafa54 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -81,13 +81,21 @@ config KVM_WERROR
 	  If in doubt, say "N".
 
 config KVM_VM_MEMORY_ATTRIBUTES
-	bool
+	bool "Enable per-VM PRIVATE vs. SHARED attributes (for CoCo VMs)"
+	depends on KVM_SW_PROTECTED_VM || KVM_INTEL_TDX || KVM_AMD_SEV
+	help
+	  Enable support for tracking PRIVATE vs. SHARED memory using per-VM
+	  memory attributes.  Using per-VM attributes is deprecated in favor of
+	  tracking PRIVATE state in guest_memfd.  Select this if you need to run
+	  CoCo VMs using a VMM that doesn't support guest_memfd memory
+	  attributes.
+
+	  If unsure, say N.
 
 config KVM_SW_PROTECTED_VM
 	bool "Enable support for KVM software-protected VMs"
 	depends on EXPERT
 	depends on KVM_X86 && X86_64
-	select KVM_VM_MEMORY_ATTRIBUTES
 	help
 	  Enable support for KVM software-protected VMs.  Currently, software-
 	  protected VMs are purely a development and testing vehicle for
@@ -138,7 +146,6 @@ config KVM_INTEL_TDX
 	bool "Intel Trust Domain Extensions (TDX) support"
 	default y
 	depends on INTEL_TDX_HOST
-	select KVM_VM_MEMORY_ATTRIBUTES
 	select HAVE_KVM_ARCH_GMEM_POPULATE
 	help
 	  Provides support for launching Intel Trust Domain Extensions (TDX)
@@ -162,7 +169,6 @@ config KVM_AMD_SEV
 	depends on KVM_AMD && X86_64
 	depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
 	select ARCH_HAS_CC_PLATFORM
-	select KVM_VM_MEMORY_ATTRIBUTES
 	select HAVE_KVM_ARCH_GMEM_CONVERT
 	select HAVE_KVM_ARCH_GMEM_RECLAIM
 	select HAVE_KVM_ARCH_GMEM_INVALIDATE
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index ea2752989f8bd..df67a6188aa99 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -1137,10 +1137,12 @@ static bool kvm_range_is_private(struct file *file, pgoff_t index,
 {
 	struct inode *inode = file_inode(file);
 
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
 	if (!gmem_in_place_conversion)
 		return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages,
 							  KVM_MEMORY_ATTRIBUTE_PRIVATE,
 							  KVM_MEMORY_ATTRIBUTE_PRIVATE);
+#endif
 
 	return kvm_gmem_range_has_attributes(inode, index, nr_pages,
 					     KVM_MEMORY_ATTRIBUTE_PRIVATE);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e961cc297ba2a..eb9f433278d2f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -102,7 +102,10 @@ static bool __ro_after_init allow_unsafe_mappings;
 module_param(allow_unsafe_mappings, bool, 0444);
 
 #ifdef kvm_arch_has_private_mem
-bool __ro_after_init gmem_in_place_conversion = false;
+bool __ro_after_init gmem_in_place_conversion = !IS_ENABLED(CONFIG_KVM_VM_MEMORY_ATTRIBUTES);
+#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
+module_param(gmem_in_place_conversion, bool, 0444);
+#endif
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(gmem_in_place_conversion);
 #endif
 

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 21/41] KVM: guest_memfd: Enable INIT_SHARED on guest_memfd for x86 Coco VMs

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Now that guest_memfd supports tracking private vs. shared within gmem
itself, allow userspace to specify INIT_SHARED on a guest_memfd instance
for x86 Confidential Computing (CoCo) VMs, so long as in-place conversion
is enabled, i.e. when it's actually possible for a guest_memfd instance to
contain shared memory.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 arch/x86/kvm/x86.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 52de3ec7c7f73..79538dedfad68 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10623,14 +10623,15 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
 }
 
 #ifdef CONFIG_KVM_GUEST_MEMFD
-/*
- * KVM doesn't yet support initializing guest_memfd memory as shared for VMs
- * with private memory (the private vs. shared tracking needs to be moved into
- * guest_memfd).
- */
 bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm)
 {
-	return !kvm_arch_has_private_mem(kvm);
+	/*
+	 * INIT_SHARED is supported if in-place conversion is enabled, or if
+	 * the VM doesn't support private memory.  If the VM has private memory
+	 * and in-place conversion is disabled, then guest_memfd can _only_ be
+	 * used for private memory.
+	 */
+	return gmem_in_place_conversion || !kvm_arch_has_private_mem(kvm);
 }
 
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 22/41] KVM: selftests: Create gmem fd before "regular" fd when adding memslot

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

When adding a memslot associated a guest_memfd instance, create/dup the
guest_memfd before creating the "normal" backing file.  This will allow
dup'ing the gmem fd as the normal fd when guest_memfd supports mmap(),
i.e. to make guest_memfd the _only_ backing source for the memslot.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/lib/kvm_util.c | 45 +++++++++++++++---------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 3794575d2ca0c..8522511c99558 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1079,6 +1079,29 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 	if (alignment > 1)
 		region->mmap_size += alignment;
 
+	if (flags & KVM_MEM_GUEST_MEMFD) {
+		if (guest_memfd < 0) {
+			u32 guest_memfd_flags = 0;
+
+			TEST_ASSERT(!guest_memfd_offset,
+				    "Offset must be zero when creating new guest_memfd");
+			guest_memfd = vm_create_guest_memfd(vm, mem_size, guest_memfd_flags);
+		} else {
+			/*
+			 * Install a unique fd for each memslot so that the fd
+			 * can be closed when the region is deleted without
+			 * needing to track if the fd is owned by the framework
+			 * or by the caller.
+			 */
+			guest_memfd = kvm_dup(guest_memfd);
+		}
+
+		region->region.guest_memfd = guest_memfd;
+		region->region.guest_memfd_offset = guest_memfd_offset;
+	} else {
+		region->region.guest_memfd = -1;
+	}
+
 	region->fd = -1;
 	if (backing_src_is_shared(src_type))
 		region->fd = kvm_memfd_alloc(region->mmap_size,
@@ -1108,28 +1131,6 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 
 	region->backing_src_type = src_type;
 
-	if (flags & KVM_MEM_GUEST_MEMFD) {
-		if (guest_memfd < 0) {
-			u32 guest_memfd_flags = 0;
-			TEST_ASSERT(!guest_memfd_offset,
-				    "Offset must be zero when creating new guest_memfd");
-			guest_memfd = vm_create_guest_memfd(vm, mem_size, guest_memfd_flags);
-		} else {
-			/*
-			 * Install a unique fd for each memslot so that the fd
-			 * can be closed when the region is deleted without
-			 * needing to track if the fd is owned by the framework
-			 * or by the caller.
-			 */
-			guest_memfd = kvm_dup(guest_memfd);
-		}
-
-		region->region.guest_memfd = guest_memfd;
-		region->region.guest_memfd_offset = guest_memfd_offset;
-	} else {
-		region->region.guest_memfd = -1;
-	}
-
 	region->unused_phy_pages = sparsebit_alloc();
 	if (vm_arch_has_protected_memory(vm))
 		region->protected_phy_pages = sparsebit_alloc();

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 23/41] KVM: selftests: Rename guest_memfd{,_offset} to gmem_{fd,offset}

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Rename local variables and function parameters for the guest memory file
descriptor and its offset to use a "gmem_" prefix instead of
"guest_memfd_".

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h |  6 +++---
 tools/testing/selftests/kvm/lib/kvm_util.c     | 26 +++++++++++++-------------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index b39e713c30a46..5adad5d4e9cd6 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -690,17 +690,17 @@ int __vm_set_user_memory_region(struct kvm_vm *vm, u32 slot, u32 flags,
 				gpa_t gpa, u64 size, void *hva);
 void vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 				gpa_t gpa, u64 size, void *hva,
-				u32 guest_memfd, u64 guest_memfd_offset);
+				u32 gmem_fd, u64 gmem_offset);
 int __vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 				 gpa_t gpa, u64 size, void *hva,
-				 u32 guest_memfd, u64 guest_memfd_offset);
+				 u32 gmem_fd, u64 gmem_offset);
 
 void vm_userspace_mem_region_add(struct kvm_vm *vm,
 				 enum vm_mem_backing_src_type src_type,
 				 gpa_t gpa, u32 slot, u64 npages, u32 flags);
 void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		gpa_t gpa, u32 slot, u64 npages, u32 flags,
-		int guest_memfd_fd, u64 guest_memfd_offset);
+		int gmem_fd, u64 gmem_offset);
 
 #ifndef vm_arch_has_protected_memory
 static inline bool vm_arch_has_protected_memory(struct kvm_vm *vm)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 8522511c99558..57512c9ed579d 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -972,7 +972,7 @@ void vm_set_user_memory_region(struct kvm_vm *vm, u32 slot, u32 flags,
 
 int __vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 				 gpa_t gpa, u64 size, void *hva,
-				 u32 guest_memfd, u64 guest_memfd_offset)
+				 u32 gmem_fd, u64 gmem_offset)
 {
 	struct kvm_userspace_memory_region2 region = {
 		.slot = slot,
@@ -980,8 +980,8 @@ int __vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 		.guest_phys_addr = gpa,
 		.memory_size = size,
 		.userspace_addr = (uintptr_t)hva,
-		.guest_memfd = guest_memfd,
-		.guest_memfd_offset = guest_memfd_offset,
+		.guest_memfd = gmem_fd,
+		.guest_memfd_offset = gmem_offset,
 	};
 
 	TEST_REQUIRE_SET_USER_MEMORY_REGION2();
@@ -991,10 +991,10 @@ int __vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 
 void vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 				gpa_t gpa, u64 size, void *hva,
-				u32 guest_memfd, u64 guest_memfd_offset)
+				u32 gmem_fd, u64 gmem_offset)
 {
 	int ret = __vm_set_user_memory_region2(vm, slot, flags, gpa, size, hva,
-					       guest_memfd, guest_memfd_offset);
+					       gmem_fd, gmem_offset);
 
 	TEST_ASSERT(!ret, "KVM_SET_USER_MEMORY_REGION2 failed, errno = %d (%s)",
 		    errno, strerror(errno));
@@ -1004,7 +1004,7 @@ void vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 /* FIXME: This thing needs to be ripped apart and rewritten. */
 void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		gpa_t gpa, u32 slot, u64 npages, u32 flags,
-		int guest_memfd, u64 guest_memfd_offset)
+		int gmem_fd, u64 gmem_offset)
 {
 	int ret;
 	struct userspace_mem_region *region;
@@ -1080,12 +1080,12 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		region->mmap_size += alignment;
 
 	if (flags & KVM_MEM_GUEST_MEMFD) {
-		if (guest_memfd < 0) {
-			u32 guest_memfd_flags = 0;
+		if (gmem_fd < 0) {
+			u32 gmem_flags = 0;
 
-			TEST_ASSERT(!guest_memfd_offset,
+			TEST_ASSERT(!gmem_offset,
 				    "Offset must be zero when creating new guest_memfd");
-			guest_memfd = vm_create_guest_memfd(vm, mem_size, guest_memfd_flags);
+			gmem_fd = vm_create_guest_memfd(vm, mem_size, gmem_flags);
 		} else {
 			/*
 			 * Install a unique fd for each memslot so that the fd
@@ -1093,11 +1093,11 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 			 * needing to track if the fd is owned by the framework
 			 * or by the caller.
 			 */
-			guest_memfd = kvm_dup(guest_memfd);
+			gmem_fd = kvm_dup(gmem_fd);
 		}
 
-		region->region.guest_memfd = guest_memfd;
-		region->region.guest_memfd_offset = guest_memfd_offset;
+		region->region.guest_memfd = gmem_fd;
+		region->region.guest_memfd_offset = gmem_offset;
 	} else {
 		region->region.guest_memfd = -1;
 	}

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 24/41] KVM: selftests: Add support for mmap() on guest_memfd in core library

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Accept gmem_flags in vm_mem_add() to be able to create a guest_memfd within
vm_mem_add().

When vm_mem_add() is used to set up a guest_memfd for a memslot, set up the
provided (or created) gmem_fd as the fd for the user memory region. This
makes it available to be mmap()-ed from just like fds from other memory
sources.

For guest_memfds, mmap() using gmem_offset instead of 0 all the time.

Always use MAP_SHARED if mmap-ing from guest_memfd instead of reading flag
from the configured src_type, which doesn't include guest_memfd.

Add a kvm_slot_to_fd() helper to provide convenient access to the file
descriptor of a memslot.

Update existing callers of vm_mem_add() to pass 0 for gmem_flags to
preserve existing behavior.

Signed-off-by: Sean Christopherson <seanjc@google.com>
[mmap() with gmem_offset, and always with MAP_SHARED.]
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h     |  7 +++++-
 tools/testing/selftests/kvm/lib/kvm_util.c         | 28 ++++++++++++----------
 .../kvm/x86/private_mem_conversions_test.c         |  2 +-
 3 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 5adad5d4e9cd6..2186e98583969 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -700,7 +700,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
 				 gpa_t gpa, u32 slot, u64 npages, u32 flags);
 void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		gpa_t gpa, u32 slot, u64 npages, u32 flags,
-		int gmem_fd, u64 gmem_offset);
+		int gmem_fd, u64 gmem_offset, u64 gmem_flags);
 
 #ifndef vm_arch_has_protected_memory
 static inline bool vm_arch_has_protected_memory(struct kvm_vm *vm)
@@ -732,6 +732,11 @@ void *addr_gva2hva(struct kvm_vm *vm, gva_t gva);
 gpa_t addr_hva2gpa(struct kvm_vm *vm, void *hva);
 void *addr_gpa2alias(struct kvm_vm *vm, gpa_t gpa);
 
+static inline int kvm_slot_to_fd(struct kvm_vm *vm, u32 slot)
+{
+	return memslot2region(vm, slot)->fd;
+}
+
 #ifndef vcpu_arch_put_guest
 #define vcpu_arch_put_guest(mem, val) do { (mem) = (val); } while (0)
 #endif
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 57512c9ed579d..2017dd34001f8 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1004,12 +1004,14 @@ void vm_set_user_memory_region2(struct kvm_vm *vm, u32 slot, u32 flags,
 /* FIXME: This thing needs to be ripped apart and rewritten. */
 void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 		gpa_t gpa, u32 slot, u64 npages, u32 flags,
-		int gmem_fd, u64 gmem_offset)
+		int gmem_fd, u64 gmem_offset, u64 gmem_flags)
 {
 	int ret;
 	struct userspace_mem_region *region;
 	size_t backing_src_pagesz = get_backing_src_pagesz(src_type);
+	int mmap_flags = vm_mem_backing_src_alias(src_type)->flag;
 	size_t mem_size = npages * vm->page_size;
+	off_t mmap_offset = 0;
 	size_t alignment = 1;
 
 	TEST_REQUIRE_SET_USER_MEMORY_REGION2();
@@ -1081,8 +1083,6 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 
 	if (flags & KVM_MEM_GUEST_MEMFD) {
 		if (gmem_fd < 0) {
-			u32 gmem_flags = 0;
-
 			TEST_ASSERT(!gmem_offset,
 				    "Offset must be zero when creating new guest_memfd");
 			gmem_fd = vm_create_guest_memfd(vm, mem_size, gmem_flags);
@@ -1103,13 +1103,17 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 	}
 
 	region->fd = -1;
-	if (backing_src_is_shared(src_type))
+	if (flags & KVM_MEM_GUEST_MEMFD && gmem_flags & GUEST_MEMFD_FLAG_MMAP) {
+		region->fd = kvm_dup(gmem_fd);
+		mmap_flags = MAP_SHARED;
+		mmap_offset = gmem_offset;
+	} else if (backing_src_is_shared(src_type)) {
 		region->fd = kvm_memfd_alloc(region->mmap_size,
 					     src_type == VM_MEM_SRC_SHARED_HUGETLB);
+	}
 
-	region->mmap_start = kvm_mmap(region->mmap_size, PROT_READ | PROT_WRITE,
-				      vm_mem_backing_src_alias(src_type)->flag,
-				      region->fd);
+	region->mmap_start = __kvm_mmap(region->mmap_size, PROT_READ | PROT_WRITE,
+					mmap_flags, region->fd, mmap_offset);
 
 	TEST_ASSERT(!is_backing_src_hugetlb(src_type) ||
 		    region->mmap_start == align_ptr_up(region->mmap_start, backing_src_pagesz),
@@ -1155,10 +1159,10 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 
 	/* If shared memory, create an alias. */
 	if (region->fd >= 0) {
-		region->mmap_alias = kvm_mmap(region->mmap_size,
-					      PROT_READ | PROT_WRITE,
-					      vm_mem_backing_src_alias(src_type)->flag,
-					      region->fd);
+		region->mmap_alias = __kvm_mmap(region->mmap_size,
+						PROT_READ | PROT_WRITE,
+						mmap_flags, region->fd,
+						mmap_offset);
 
 		/* Align host alias address */
 		region->host_alias = align_ptr_up(region->mmap_alias, alignment);
@@ -1169,7 +1173,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
 				 enum vm_mem_backing_src_type src_type,
 				 gpa_t gpa, u32 slot, u64 npages, u32 flags)
 {
-	vm_mem_add(vm, src_type, gpa, slot, npages, flags, -1, 0);
+	vm_mem_add(vm, src_type, gpa, slot, npages, flags, -1, 0, 0);
 }
 
 /*
diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
index 1d2f5d4fd45d7..861baff201e78 100644
--- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
@@ -399,7 +399,7 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_v
 	for (i = 0; i < nr_memslots; i++)
 		vm_mem_add(vm, src_type, BASE_DATA_GPA + slot_size * i,
 			   BASE_DATA_SLOT + i, slot_size / vm->page_size,
-			   KVM_MEM_GUEST_MEMFD, memfd, slot_size * i);
+			   KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, 0);
 
 	for (i = 0; i < nr_vcpus; i++) {
 		gpa_t gpa =  BASE_DATA_GPA + i * per_cpu_size;

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 25/41] KVM: selftests: Add selftests global for guest memory attributes capability

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Add a global variable, kvm_has_gmem_attributes, to make the result of
checking for KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES available to all tests.

kvm_has_gmem_attributes is true if guest_memfd tracks memory attributes, as
opposed to VM-level tracking.

This global variable is synced to the guest for testing convenience, to
avoid introducing subtle bugs when host/guest state is desynced.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/test_util.h | 2 ++
 tools/testing/selftests/kvm/lib/kvm_util.c      | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index d64c8a228207a..c6492a29ee901 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -115,6 +115,8 @@ struct kvm_random_state {
 extern u32 kvm_random_seed;
 extern struct kvm_random_state kvm_rng;
 
+extern bool kvm_has_gmem_attributes;
+
 struct kvm_random_state new_kvm_random_state(u32 seed);
 u32 kvm_random_u32(struct kvm_random_state *state);
 
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 2017dd34001f8..e706669596947 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -32,6 +32,8 @@ static void kvm_seed_rng(u32 seed)
 	kvm_rng = new_kvm_random_state(kvm_random_seed);
 }
 
+bool kvm_has_gmem_attributes;
+
 static size_t vcpu_mmap_sz(void);
 
 int __open_path_or_exit(const char *path, int flags, const char *enoent_help)
@@ -527,6 +529,7 @@ struct kvm_vm *__vm_create(struct vm_shape shape, u32 nr_runnable_vcpus,
 		kvm_seed_rng(kvm_random_seed);
 
 	sync_global_to_guest(vm, kvm_rng);
+	sync_global_to_guest(vm, kvm_has_gmem_attributes);
 
 	kvm_arch_vm_post_create(vm, nr_runnable_vcpus);
 
@@ -2313,6 +2316,8 @@ void __attribute((constructor)) kvm_selftest_init(void)
 	srandom(time(0));
 	kvm_seed_rng(random());
 
+	kvm_has_gmem_attributes = kvm_has_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES);
+
 	kvm_selftest_arch_init();
 }
 

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 26/41] KVM: selftests: Add helpers for calling ioctls on guest_memfd

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Add helper functions to kvm_util.h to support calling ioctls, specifically
KVM_SET_MEMORY_ATTRIBUTES2, on a guest_memfd file descriptor.

Introduce gmem_ioctl() and __gmem_ioctl() macros, modeled after the
existing vm_ioctl() helpers, to provide a standard way to call ioctls
on a guest_memfd.

Add gmem_set_memory_attributes() and its derivatives (gmem_set_private(),
gmem_set_shared()) to set memory attributes on a guest_memfd region.
Also provide "__" variants that return the ioctl error code instead of
aborting the test. These helpers will be used by upcoming guest_memfd
tests.

To avoid code duplication, factor out the check for supported memory
attributes into a new macro, TEST_ASSERT_SUPPORTED_ATTRIBUTES, and use
it in both the existing vm_set_memory_attributes() and the new
gmem_set_memory_attributes() helpers.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h | 94 +++++++++++++++++++++++---
 1 file changed, 86 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 2186e98583969..626c960b4bb82 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -392,6 +392,16 @@ static __always_inline void static_assert_is_vcpu(struct kvm_vcpu *vcpu) { }
 	__TEST_ASSERT_VM_VCPU_IOCTL(!ret, #cmd, ret, (vcpu)->vm);	\
 })
 
+#define __gmem_ioctl(gmem_fd, cmd, arg)				\
+	kvm_do_ioctl(gmem_fd, cmd, arg)
+
+#define gmem_ioctl(gmem_fd, cmd, arg)				\
+({								\
+	int ret = __gmem_ioctl(gmem_fd, cmd, arg);		\
+								\
+	TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(#cmd, ret));	\
+})
+
 /*
  * Looks up and returns the value corresponding to the capability
  * (KVM_CAP_*) given by cap.
@@ -418,8 +428,16 @@ static inline void vm_enable_cap(struct kvm_vm *vm, u32 cap, u64 arg0)
 	vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap);
 }
 
+/*
+ * KVM_SET_MEMORY_ATTRIBUTES{,2} overwrites _all_ attributes.  These
+ * flows need significant enhancements to support multiple attributes.
+ */
+#define TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes)				\
+	TEST_ASSERT(!(attributes) || (attributes) == KVM_MEMORY_ATTRIBUTE_PRIVATE,	\
+		    "Update me to support multiple attributes!")
+
 static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
-					    u64 size, u64 attributes)
+					    size_t size, u64 attributes)
 {
 	struct kvm_memory_attributes attr = {
 		.attributes = attributes,
@@ -428,17 +446,11 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
 		.flags = 0,
 	};
 
-	/*
-	 * KVM_SET_MEMORY_ATTRIBUTES overwrites _all_ attributes.  These flows
-	 * need significant enhancements to support multiple attributes.
-	 */
-	TEST_ASSERT(!attributes || attributes == KVM_MEMORY_ATTRIBUTE_PRIVATE,
-		    "Update me to support multiple attributes!");
+	TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes);
 
 	vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr);
 }
 
-
 static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
 				      u64 size)
 {
@@ -451,6 +463,72 @@ static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
 	vm_set_memory_attributes(vm, gpa, size, 0);
 }
 
+static inline int __gmem_set_memory_attributes(int fd, u64 offset,
+					       size_t size, u64 attributes,
+					       u64 *error_offset)
+{
+	struct kvm_memory_attributes2 attr = {
+		.attributes = attributes,
+		.offset = offset,
+		.size = size,
+		.flags = 0,
+		.error_offset = 0,
+	};
+	int r;
+
+	r = __gmem_ioctl(fd, KVM_SET_MEMORY_ATTRIBUTES2, &attr);
+
+	/* Copy error_offset regardless of r so caller can check. */
+	if (error_offset)
+		*error_offset = attr.error_offset;
+
+	return r;
+}
+
+static inline int __gmem_set_private(int fd, u64 offset, size_t size,
+				     u64 *error_offset)
+{
+	return __gmem_set_memory_attributes(fd, offset, size,
+					    KVM_MEMORY_ATTRIBUTE_PRIVATE,
+					    error_offset);
+}
+
+static inline int __gmem_set_shared(int fd, u64 offset, size_t size,
+				    u64 *error_offset)
+{
+	return __gmem_set_memory_attributes(fd, offset, size, 0,
+					    error_offset);
+}
+
+static inline void gmem_set_memory_attributes(int fd, u64 offset,
+					      size_t size, u64 attributes)
+{
+	struct kvm_memory_attributes2 attr = {
+		.attributes = attributes,
+		.offset = offset,
+		.size = size,
+		.flags = 0,
+	};
+
+	TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes);
+
+	__TEST_REQUIRE(kvm_check_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES) > 0,
+		       "No valid attributes for guest_memfd ioctl!");
+
+	gmem_ioctl(fd, KVM_SET_MEMORY_ATTRIBUTES2, &attr);
+}
+
+static inline void gmem_set_private(int fd, u64 offset, size_t size)
+{
+	gmem_set_memory_attributes(fd, offset, size,
+				   KVM_MEMORY_ATTRIBUTE_PRIVATE);
+}
+
+static inline void gmem_set_shared(int fd, u64 offset, size_t size)
+{
+	gmem_set_memory_attributes(fd, offset, size, 0);
+}
+
 void vm_guest_mem_fallocate(struct kvm_vm *vm, gpa_t gpa, u64 size,
 			    bool punch_hole);
 

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 27/41] KVM: selftests: Test basic single-page conversion flow

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add a selftest for the guest_memfd memory attribute conversion ioctls.
The test starts the guest_memfd as all-private (the default state), and
verifies the basic flow of converting a single page to shared and then back
to private.

Add infrastructure that supports extensions to other conversion flow
tests. This infrastructure will be used in upcoming patches for other
conversion tests.

Add test as an x86-specific test since guest_memfd's testing
vehicle (KVM_X86_SW_PROTECTED_VM) is x86-specific.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/Makefile.kvm           |   1 +
 .../kvm/x86/guest_memfd_conversions_test.c         | 199 +++++++++++++++++++++
 2 files changed, 200 insertions(+)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 88c6c8046ddec..daecab00fc984 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -153,6 +153,7 @@ TEST_GEN_PROGS_x86 += x86/max_vcpuid_cap_test
 TEST_GEN_PROGS_x86 += x86/triple_fault_event_test
 TEST_GEN_PROGS_x86 += x86/recalc_apic_map_test
 TEST_GEN_PROGS_x86 += x86/aperfmperf_test
+TEST_GEN_PROGS_x86 += x86/guest_memfd_conversions_test
 TEST_GEN_PROGS_x86 += access_tracking_perf_test
 TEST_GEN_PROGS_x86 += coalesced_io_test
 TEST_GEN_PROGS_x86 += dirty_log_perf_test
diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
new file mode 100644
index 0000000000000..8e09e241723e5
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024, Google LLC.
+ */
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include <linux/align.h>
+#include <linux/kvm.h>
+#include <linux/sizes.h>
+
+#include "kvm_util.h"
+#include "kselftest_harness.h"
+#include "test_util.h"
+#include "ucall_common.h"
+
+FIXTURE(gmem_conversions) {
+	struct kvm_vcpu *vcpu;
+	int gmem_fd;
+	/* HVA of the first byte of the memory mmap()-ed from gmem_fd. */
+	char *mem;
+};
+
+typedef FIXTURE_DATA(gmem_conversions) test_data_t;
+
+FIXTURE_SETUP(gmem_conversions) { }
+
+static size_t page_size;
+
+static void guest_do_rmw(void);
+#define GUEST_MEMFD_SHARING_TEST_GVA 0x90000000ULL
+
+/*
+ * Defer setup until the individual test is invoked so that tests can specify
+ * the number of pages and flags for the guest_memfd instance.
+ */
+static void gmem_conversions_do_setup(test_data_t *t, int nr_pages,
+				      int gmem_flags)
+{
+	const struct vm_shape shape = {
+		.mode = VM_MODE_DEFAULT,
+		.type = KVM_X86_SW_PROTECTED_VM,
+	};
+	/*
+	 * Use high GPA above APIC_DEFAULT_PHYS_BASE to avoid clashing with
+	 * APIC_DEFAULT_PHYS_BASE.
+	 */
+	const gpa_t gpa = SZ_4G;
+	const u32 slot = 1;
+	struct kvm_vm *vm;
+
+	vm = __vm_create_shape_with_one_vcpu(shape, &t->vcpu, nr_pages, guest_do_rmw);
+
+	vm_mem_add(vm, VM_MEM_SRC_SHMEM, gpa, slot, nr_pages,
+		   KVM_MEM_GUEST_MEMFD, -1, 0, gmem_flags);
+
+	t->gmem_fd = kvm_slot_to_fd(vm, slot);
+	t->mem = addr_gpa2hva(vm, gpa);
+	virt_map(vm, GUEST_MEMFD_SHARING_TEST_GVA, gpa, nr_pages);
+}
+
+static void gmem_conversions_do_teardown(test_data_t *t)
+{
+	/* No need to close gmem_fd, it's owned by the VM structure. */
+	kvm_vm_free(t->vcpu->vm);
+}
+
+FIXTURE_TEARDOWN(gmem_conversions)
+{
+	gmem_conversions_do_teardown(self);
+}
+
+/*
+ * In these test definition macros, __nr_pages and nr_pages is used to set up
+ * the total number of pages in the guest_memfd under test. This will be
+ * available in the test definitions as nr_pages.
+ */
+
+#define __GMEM_CONVERSION_TEST(test, __nr_pages, flags)				\
+static void __gmem_conversions_##test(test_data_t *t, int nr_pages);		\
+										\
+TEST_F(gmem_conversions, test)							\
+{										\
+	gmem_conversions_do_setup(self, __nr_pages, flags);			\
+	__gmem_conversions_##test(self, __nr_pages);				\
+}										\
+static void __gmem_conversions_##test(test_data_t *t, int nr_pages)		\
+
+#define GMEM_CONVERSION_TEST(test, __nr_pages, flags)				\
+	__GMEM_CONVERSION_TEST(test, __nr_pages, (flags) | GUEST_MEMFD_FLAG_MMAP)
+
+#define __GMEM_CONVERSION_TEST_INIT_PRIVATE(test, __nr_pages)			\
+	GMEM_CONVERSION_TEST(test, __nr_pages, 0)
+
+#define GMEM_CONVERSION_TEST_INIT_PRIVATE(test)					\
+	__GMEM_CONVERSION_TEST_INIT_PRIVATE(test, 1)
+
+struct guest_check_data {
+	void *mem;
+	char expected_val;
+	char write_val;
+};
+static struct guest_check_data guest_data;
+
+static void guest_do_rmw(void)
+{
+	for (;;) {
+		char *mem = READ_ONCE(guest_data.mem);
+
+		GUEST_ASSERT_EQ(READ_ONCE(*mem), READ_ONCE(guest_data.expected_val));
+		WRITE_ONCE(*mem, READ_ONCE(guest_data.write_val));
+
+		GUEST_SYNC(0);
+	}
+}
+
+static void run_guest_do_rmw(struct kvm_vcpu *vcpu, u64 pgoff,
+			     char expected_val, char write_val)
+{
+	struct ucall uc;
+	int r;
+
+	guest_data.mem = (void *)GUEST_MEMFD_SHARING_TEST_GVA + pgoff * page_size;
+	guest_data.expected_val = expected_val;
+	guest_data.write_val = write_val;
+	sync_global_to_guest(vcpu->vm, guest_data);
+
+	do {
+		r = __vcpu_run(vcpu);
+	} while (r == -1 && errno == EINTR);
+
+	TEST_ASSERT_EQ(r, 0);
+
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT(uc);
+	case UCALL_SYNC:
+		break;
+	default:
+		TEST_FAIL("Unexpected ucall %lu", uc.cmd);
+	}
+}
+
+static void host_do_rmw(char *mem, u64 pgoff, char expected_val,
+			char write_val)
+{
+	TEST_ASSERT_EQ(READ_ONCE(mem[pgoff * page_size]), expected_val);
+	WRITE_ONCE(mem[pgoff * page_size], write_val);
+}
+
+static void test_private(test_data_t *t, u64 pgoff, char starting_val,
+			 char write_val)
+{
+	TEST_EXPECT_SIGBUS(WRITE_ONCE(t->mem[pgoff * page_size], write_val));
+	run_guest_do_rmw(t->vcpu, pgoff, starting_val, write_val);
+	TEST_EXPECT_SIGBUS(READ_ONCE(t->mem[pgoff * page_size]));
+}
+
+static void test_convert_to_private(test_data_t *t, u64 pgoff,
+				    char starting_val, char write_val)
+{
+	gmem_set_private(t->gmem_fd, pgoff * page_size, page_size);
+	test_private(t, pgoff, starting_val, write_val);
+}
+
+static void test_shared(test_data_t *t, u64 pgoff, char starting_val,
+			char host_write_val, char write_val)
+{
+	host_do_rmw(t->mem, pgoff, starting_val, host_write_val);
+	run_guest_do_rmw(t->vcpu, pgoff, host_write_val, write_val);
+	TEST_ASSERT_EQ(READ_ONCE(t->mem[pgoff * page_size]), write_val);
+}
+
+static void test_convert_to_shared(test_data_t *t, u64 pgoff,
+				   char starting_val, char host_write_val,
+				   char write_val)
+{
+	gmem_set_shared(t->gmem_fd, pgoff * page_size, page_size);
+	test_shared(t, pgoff, starting_val, host_write_val, write_val);
+}
+
+GMEM_CONVERSION_TEST_INIT_PRIVATE(init_private)
+{
+	test_private(t, 0, 0, 'A');
+	test_convert_to_shared(t, 0, 'A', 'B', 'C');
+	test_convert_to_private(t, 0, 'C', 'E');
+}
+
+
+int main(int argc, char *argv[])
+{
+	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
+	TEST_REQUIRE(kvm_check_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES) &
+		     KVM_MEMORY_ATTRIBUTE_PRIVATE);
+
+	page_size = getpagesize();
+
+	return test_harness_run(argc, argv);
+}

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 28/41] KVM: selftests: Test conversion flow when INIT_SHARED

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add a test case to verify that conversions between private and shared
memory work correctly when the memory is initially created as shared.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../testing/selftests/kvm/x86/guest_memfd_conversions_test.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
index 8e09e241723e5..5b070d3374eae 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -95,6 +95,12 @@ static void __gmem_conversions_##test(test_data_t *t, int nr_pages)		\
 #define GMEM_CONVERSION_TEST_INIT_PRIVATE(test)					\
 	__GMEM_CONVERSION_TEST_INIT_PRIVATE(test, 1)
 
+#define __GMEM_CONVERSION_TEST_INIT_SHARED(test, __nr_pages)			\
+	GMEM_CONVERSION_TEST(test, __nr_pages, GUEST_MEMFD_FLAG_INIT_SHARED)
+
+#define GMEM_CONVERSION_TEST_INIT_SHARED(test)					\
+	__GMEM_CONVERSION_TEST_INIT_SHARED(test, 1)
+
 struct guest_check_data {
 	void *mem;
 	char expected_val;
@@ -186,6 +192,12 @@ GMEM_CONVERSION_TEST_INIT_PRIVATE(init_private)
 	test_convert_to_private(t, 0, 'C', 'E');
 }
 
+GMEM_CONVERSION_TEST_INIT_SHARED(init_shared)
+{
+	test_shared(t, 0, 0, 'A', 'B');
+	test_convert_to_private(t, 0, 'B', 'C');
+	test_convert_to_shared(t, 0, 'C', 'D', 'E');
+}
 
 int main(int argc, char *argv[])
 {

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 29/41] KVM: selftests: Test conversion precision in guest_memfd

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

The existing guest_memfd conversion tests only use single-page memory
regions. This provides no coverage for multi-page guest_memfd objects,
specifically whether KVM correctly handles the page index for conversion
operations. An incorrect implementation could, for example, always operate
on the first page regardless of the index provided.

Add a new test case to verify that conversions between private and shared
memory correctly target the specified page within a multi-page guest_memfd.

This test also verifies the precision of memory conversions by converting a
single page an then iterating through all other pages ensure they remain in
their original state.

To support this test, add a new GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED
macro that handles setting up and tearing down the VM for each page
iteration. The teardown logic is adjusted to prevent a double-free in this
new scenario.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../kvm/x86/guest_memfd_conversions_test.c         | 66 ++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
index 5b070d3374eae..8e17d5c08aeb8 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -61,8 +61,13 @@ static void gmem_conversions_do_setup(test_data_t *t, int nr_pages,
 
 static void gmem_conversions_do_teardown(test_data_t *t)
 {
+	/* Use NULL to avoid second free in FIXTURE_TEARDOWN (multipage tests). */
+	if (!t->vcpu)
+		return;
+
 	/* No need to close gmem_fd, it's owned by the VM structure. */
 	kvm_vm_free(t->vcpu->vm);
+	t->vcpu = NULL;
 }
 
 FIXTURE_TEARDOWN(gmem_conversions)
@@ -101,6 +106,29 @@ static void __gmem_conversions_##test(test_data_t *t, int nr_pages)		\
 #define GMEM_CONVERSION_TEST_INIT_SHARED(test)					\
 	__GMEM_CONVERSION_TEST_INIT_SHARED(test, 1)
 
+/*
+ * Repeats test over nr_pages in a guest_memfd of size nr_pages, providing each
+ * test iteration with test_page, the index of the page under test in
+ * guest_memfd. test_page takes values 0..(nr_pages - 1) inclusive.
+ */
+#define GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(test, __nr_pages)		\
+static void __gmem_conversions_multipage_##test(test_data_t *t, int nr_pages,	\
+						const int test_page);		\
+										\
+TEST_F(gmem_conversions, test)							\
+{										\
+	const u64 flags = GUEST_MEMFD_FLAG_MMAP | GUEST_MEMFD_FLAG_INIT_SHARED; \
+	int i;									\
+										\
+	for (i = 0; i < __nr_pages; ++i) {					\
+		gmem_conversions_do_setup(self, __nr_pages, flags);		\
+		__gmem_conversions_multipage_##test(self, __nr_pages, i);	\
+		gmem_conversions_do_teardown(self);				\
+	}									\
+}										\
+static void __gmem_conversions_multipage_##test(test_data_t *t, int nr_pages,	\
+						const int test_page)
+
 struct guest_check_data {
 	void *mem;
 	char expected_val;
@@ -199,6 +227,44 @@ GMEM_CONVERSION_TEST_INIT_SHARED(init_shared)
 	test_convert_to_shared(t, 0, 'C', 'D', 'E');
 }
 
+GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(indexing, 4)
+{
+	int i;
+
+	/* Get a char that varies with both i and n. */
+#define combine(x, n) ((x << 4) + (n))
+#define i_(n) (combine(i, n))
+#define t_(n) (combine(test_page, n))
+
+	/*
+	 * Start with the highest index, to catch any errors when, perhaps, the
+	 * first page is returned even for the last index.
+	 */
+	for (i = nr_pages - 1; i >= 0; --i)
+		test_shared(t, i, 0, i_(0), i_(2));
+
+	test_convert_to_private(t, test_page, t_(2), t_(3));
+
+	for (i = 0; i < nr_pages; ++i) {
+		if (i == test_page)
+			test_private(t, test_page, t_(3), t_(4));
+		else
+			test_shared(t, i, i_(2), i_(3), i_(4));
+	}
+
+	test_convert_to_shared(t, test_page, t_(4), t_(5), t_(6));
+
+	for (i = 0; i < nr_pages; ++i) {
+		char expected = i == test_page ? t_(6) : i_(4);
+
+		test_shared(t, i, expected, i_(7), i_(8));
+	}
+
+#undef t_
+#undef i_
+#undef combine
+}
+
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 30/41] KVM: selftests: Test conversion before allocation

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add two test cases to the guest_memfd conversions selftest to cover
the scenario where a conversion is requested before any memory has been
allocated in the guest_memfd region.

The KVM_SET_MEMORY_ATTRIBUTES2 ioctl can be called on a memory region at
any time. If the guest had not yet faulted in any pages for that region,
the kernel must record the conversion request and apply the requested state
when the pages are eventually allocated.

The new tests cover both conversion directions.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../selftests/kvm/x86/guest_memfd_conversions_test.c       | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
index 8e17d5c08aeb8..b43ac196330f1 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -265,6 +265,20 @@ GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(indexing, 4)
 #undef combine
 }
 
+/*
+ * Test that even if there are no folios yet, conversion requests are recorded
+ * in guest_memfd.
+ */
+GMEM_CONVERSION_TEST_INIT_SHARED(before_allocation_shared)
+{
+	test_convert_to_private(t, 0, 0, 'A');
+}
+
+GMEM_CONVERSION_TEST_INIT_PRIVATE(before_allocation_private)
+{
+	test_convert_to_shared(t, 0, 0, 'A', 'B');
+}
+
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 31/41] KVM: selftests: Convert with allocated folios in different layouts

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add a guest_memfd selftest to verify that memory conversions work
correctly with allocated folios in different layouts.

By iterating through which pages are initially faulted, the test covers
various layouts of contiguous allocated and unallocated regions, exercising
conversion with different range layouts.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../kvm/x86/guest_memfd_conversions_test.c         | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
index b43ac196330f1..0b024fb7227f0 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -279,6 +279,36 @@ GMEM_CONVERSION_TEST_INIT_PRIVATE(before_allocation_private)
 	test_convert_to_shared(t, 0, 0, 'A', 'B');
 }
 
+/*
+ * Test that when some of the folios in the conversion range are allocated,
+ * conversion requests are handled correctly in guest_memfd.  Vary the ranges
+ * allocated before conversion, using test_page, to cover various layouts of
+ * contiguous allocated and unallocated regions.
+ */
+GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(unallocated_folios, 8)
+{
+	const int second_page_to_fault = 4;
+	int i;
+
+	/*
+	 * Fault 2 of the pages to test filemap range operations except when
+	 * test_page == second_page_to_fault.
+	 */
+	host_do_rmw(t->mem, test_page, 0, 'A');
+	if (test_page != second_page_to_fault)
+		host_do_rmw(t->mem, second_page_to_fault, 0, 'A');
+
+	gmem_set_private(t->gmem_fd, 0, nr_pages * page_size);
+	for (i = 0; i < nr_pages; ++i) {
+		char expected = (i == test_page || i == second_page_to_fault) ? 'A' : 0;
+
+		test_private(t, i, expected, 'B');
+	}
+
+	for (i = 0; i < nr_pages; ++i)
+		test_convert_to_shared(t, i, 'B', 'C', 'D');
+}
+
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 32/41] KVM: selftests: Test that truncation does not change shared/private status

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add a test to verify that deallocating a page in a guest memfd region via
fallocate() with FALLOC_FL_PUNCH_HOLE does not alter the shared or private
status of the corresponding memory range.

When a page backing a guest memfd mapping is deallocated, e.g., by punching
a hole or truncating the file, and then subsequently faulted back in, the
new page must inherit the correct shared/private status tracked by
guest_memfd.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../selftests/kvm/x86/guest_memfd_conversions_test.c       | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
index 0b024fb7227f0..f03af2c46426f 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -10,6 +10,7 @@
 #include <linux/sizes.h>
 
 #include "kvm_util.h"
+#include "kvm_syscalls.h"
 #include "kselftest_harness.h"
 #include "test_util.h"
 #include "ucall_common.h"
@@ -309,6 +310,19 @@ GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(unallocated_folios, 8)
 		test_convert_to_shared(t, i, 'B', 'C', 'D');
 }
 
+/* Truncation should not affect shared/private status. */
+GMEM_CONVERSION_TEST_INIT_SHARED(truncate)
+{
+	host_do_rmw(t->mem, 0, 0, 'A');
+	kvm_fallocate(t->gmem_fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size);
+	host_do_rmw(t->mem, 0, 0, 'A');
+
+	test_convert_to_private(t, 0, 'A', 'B');
+
+	kvm_fallocate(t->gmem_fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size);
+	test_private(t, 0, 0, 'A');
+}
+
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 33/41] KVM: selftests: Test that shared/private status is consistent across processes

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Add a test to verify that a guest_memfd's shared/private status is
consistent across processes, and that any shared pages previously mapped in
any process are unmapped from all processes.

The test forks a child process after creating the shared guest_memfd
region so that the second process exists alongside the main process for the
entire test.

The processes then take turns to access memory to check that the
shared/private status is consistent across processes.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../kvm/x86/guest_memfd_conversions_test.c         | 118 +++++++++++++++++++++
 1 file changed, 118 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
index f03af2c46426f..e681dac14e865 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -2,7 +2,9 @@
 /*
  * Copyright (c) 2024, Google LLC.
  */
+#include <pthread.h>
 #include <sys/mman.h>
+#include <time.h>
 #include <unistd.h>
 
 #include <linux/align.h>
@@ -323,6 +325,122 @@ GMEM_CONVERSION_TEST_INIT_SHARED(truncate)
 	test_private(t, 0, 0, 'A');
 }
 
+/* Test that shared/private memory protections work and are seen from any process. */
+GMEM_CONVERSION_TEST_INIT_SHARED(forked_accesses)
+{
+	enum test_state {
+		STATE_INIT,
+		STATE_CHECK_SHARED,
+		STATE_DONE_CHECKING_SHARED,
+		STATE_CHECK_PRIVATE,
+		STATE_DONE_CHECKING_PRIVATE,
+	};
+
+	struct sync_state {
+		pthread_mutex_t mutex;
+		pthread_cond_t cond;
+		enum test_state step;
+	} *sync;
+
+	pthread_mutexattr_t mattr;
+	pthread_condattr_t cattr;
+	pid_t child_pid, parent_pid;
+	int status;
+
+	sync = kvm_mmap(sizeof(*sync), PROT_READ | PROT_WRITE,
+			MAP_SHARED | MAP_ANONYMOUS, -1);
+
+	pthread_mutexattr_init(&mattr);
+	pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
+	pthread_mutex_init(&sync->mutex, &mattr);
+	pthread_mutexattr_destroy(&mattr);
+
+	pthread_condattr_init(&cattr);
+	pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
+	pthread_cond_init(&sync->cond, &cattr);
+	pthread_condattr_destroy(&cattr);
+
+	sync->step = STATE_INIT;
+
+#define TEST_STATE_AWAIT(__state)						\
+	do {									\
+		pthread_mutex_lock(&sync->mutex);				\
+		while (sync->step != (__state)) {				\
+			struct timespec ts, stop;				\
+			int ret;						\
+										\
+			clock_gettime(CLOCK_REALTIME, &ts);			\
+			stop = timespec_add_ns(ts, 100 * 1000000UL);		\
+										\
+			ret = pthread_cond_timedwait(&sync->cond, &sync->mutex, &stop); \
+			if (ret == ETIMEDOUT) {					\
+				bool alive = (child_pid == 0) ?			\
+					     (getppid() == parent_pid) :		\
+					     (waitpid(child_pid, NULL, WNOHANG) == 0); \
+				TEST_ASSERT(alive, "Other process exited prematurely"); \
+			} else {						\
+				TEST_ASSERT(!ret, "pthread_cond_timedwait failed"); \
+			}							\
+		}								\
+		pthread_mutex_unlock(&sync->mutex);				\
+	} while (0)
+
+#define TEST_STATE_SET(__state)							\
+	do {									\
+		pthread_mutex_lock(&sync->mutex);				\
+		sync->step = (__state);						\
+		pthread_cond_broadcast(&sync->cond);				\
+		pthread_mutex_unlock(&sync->mutex);				\
+	} while (0)
+
+	parent_pid = getpid();
+	child_pid = fork();
+	TEST_ASSERT(child_pid != -1, "fork failed");
+
+	if (child_pid == 0) {
+		const char inconsequential = 0xdd;
+
+		TEST_STATE_AWAIT(STATE_CHECK_SHARED);
+
+		/*
+		 * This maps the pages into the child process as well, and tests
+		 * that the conversion process will unmap the guest_memfd memory
+		 * from all processes.
+		 */
+		host_do_rmw(t->mem, 0, 0xB, 0xC);
+
+		TEST_STATE_SET(STATE_DONE_CHECKING_SHARED);
+		TEST_STATE_AWAIT(STATE_CHECK_PRIVATE);
+
+		TEST_EXPECT_SIGBUS(READ_ONCE(t->mem[0]));
+		TEST_EXPECT_SIGBUS(WRITE_ONCE(t->mem[0], inconsequential));
+
+		TEST_STATE_SET(STATE_DONE_CHECKING_PRIVATE);
+		exit(0);
+	}
+
+	test_shared(t, 0, 0, 0xA, 0xB);
+
+	TEST_STATE_SET(STATE_CHECK_SHARED);
+	TEST_STATE_AWAIT(STATE_DONE_CHECKING_SHARED);
+
+	test_convert_to_private(t, 0, 0xC, 0xD);
+
+	TEST_STATE_SET(STATE_CHECK_PRIVATE);
+	TEST_STATE_AWAIT(STATE_DONE_CHECKING_PRIVATE);
+
+	TEST_ASSERT_EQ(waitpid(child_pid, &status, 0), child_pid);
+	TEST_ASSERT(WIFEXITED(status) && WEXITSTATUS(status) == 0,
+		    "Child exited with unexpected status");
+
+	pthread_mutex_destroy(&sync->mutex);
+	pthread_cond_destroy(&sync->cond);
+	kvm_munmap(sync, sizeof(*sync));
+
+#undef TEST_STATE_SET
+#undef TEST_STATE_AWAIT
+}
+
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 34/41] KVM: selftests: Add helpers to pin pages with CONFIG_GUP_TEST

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add helper functions to allow KVM selftests to pin memory using
CONFIG_GUP_TEST. This is useful for testing scenarios where some page has
an increased refcount. such as in guest_memfd in-place conversion tests.

The helpers open /sys/kernel/debug/gup_test and invoke the
PIN_LONGTERM_TEST_START and PIN_LONGTERM_TEST_STOP ioctls. Since this
functionality depends on the kernel being built with CONFIG_GUP_TEST,
provide stub implementations that trigger a test failure if the
configuration is missing.

Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h |  3 +++
 tools/testing/selftests/kvm/lib/kvm_util.c     | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 626c960b4bb82..b726e49a3cfcf 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -1197,6 +1197,9 @@ static inline int pin_self_to_any_cpu(void)
 	return pin_task_to_any_cpu(pthread_self());
 }
 
+void pin_pages(void *vaddr, uint64_t size);
+void unpin_pages(void);
+
 void kvm_print_vcpu_pinning_help(void);
 void kvm_parse_vcpu_pinning(const char *pcpus_string, u32 vcpu_to_pcpu[],
 			    int nr_vcpus);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index e706669596947..ae0d7ff13f9f5 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -19,6 +19,8 @@
 #include <unistd.h>
 #include <linux/kernel.h>
 
+#include "../../../../../mm/gup_test.h"
+
 #define KVM_UTIL_MIN_PFN	2
 
 u32 kvm_random_seed;
@@ -645,6 +647,29 @@ int __pin_task_to_cpu(pthread_t task, int cpu)
 	return pthread_setaffinity_np(task, sizeof(cpuset), &cpuset);
 }
 
+static int gup_test_fd = -1;
+
+void pin_pages(void *vaddr, uint64_t size)
+{
+	const struct pin_longterm_test args = {
+		.addr = (uint64_t)vaddr,
+		.size = size,
+		.flags = PIN_LONGTERM_TEST_FLAG_USE_WRITE,
+	};
+
+	gup_test_fd = __open_path_or_exit("/sys/kernel/debug/gup_test", O_RDWR,
+					  "Is CONFIG_GUP_TEST enabled?");
+
+	TEST_ASSERT_EQ(ioctl(gup_test_fd, PIN_LONGTERM_TEST_START, &args), 0);
+}
+
+void unpin_pages(void)
+{
+	TEST_ASSERT_EQ(ioctl(gup_test_fd, PIN_LONGTERM_TEST_STOP), 0);
+
+	kvm_free_fd(gup_test_fd);
+}
+
 static u32 parse_pcpu(const char *cpu_str, const cpu_set_t *allowed_mask)
 {
 	u32 pcpu = atoi_non_negative("CPU number", cpu_str);

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 35/41] KVM: selftests: Test conversion with elevated page refcount

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Add a selftest to verify that converting a shared guest_memfd page to a
private page fails if the page has an elevated reference count.

When KVM converts a shared page to a private one, it expects the page to
have a reference count equal to the reference counts taken by the
filemap. If another kernel subsystem holds a reference to the page, the
conversion must be aborted.

The test asserts that both bulk and single-page conversion attempts
correctly fail with EAGAIN for the pinned page. After the page is unpinned,
the test verifies that subsequent conversions succeed.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../kvm/x86/guest_memfd_conversions_test.c         | 56 ++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
index e681dac14e865..50a478f9cb596 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
@@ -441,6 +441,62 @@ GMEM_CONVERSION_TEST_INIT_SHARED(forked_accesses)
 #undef TEST_STATE_AWAIT
 }
 
+static void test_convert_to_private_fails(test_data_t *t, u64 pgoff,
+					  size_t nr_pages,
+					  u64 expected_error_offset)
+{
+	/* +1 to make it anything but expected_error_offset. */
+	u64 error_offset = expected_error_offset + 1;
+	u64 offset = pgoff * page_size;
+	int ret;
+
+	do {
+		ret = __gmem_set_private(t->gmem_fd, offset,
+					 nr_pages * page_size, &error_offset);
+	} while (ret == -1 && errno == EINTR);
+	TEST_ASSERT(ret == -1 && errno == EAGAIN,
+		    "Wanted EAGAIN on page %lu, got %d (ret = %d)", pgoff,
+		    errno, ret);
+	TEST_ASSERT_EQ(error_offset, expected_error_offset);
+}
+
+GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(elevated_refcount, 4)
+{
+	int i;
+
+	pin_pages(t->mem + test_page * page_size, page_size);
+
+	for (i = 0; i < nr_pages; i++)
+		test_shared(t, i, 0, 'A', 'B');
+
+	/*
+	 * Converting in bulk should fail as long any page in the range has
+	 * unexpected refcounts.
+	 */
+	test_convert_to_private_fails(t, 0, nr_pages, test_page * page_size);
+
+	for (i = 0; i < nr_pages; i++) {
+		/*
+		 * Converting page-wise should also fail as long any page in the
+		 * range has unexpected refcounts.
+		 */
+		if (i == test_page)
+			test_convert_to_private_fails(t, i, 1, test_page * page_size);
+		else
+			test_convert_to_private(t, i, 'B', 'C');
+	}
+
+	unpin_pages();
+
+	gmem_set_private(t->gmem_fd, 0, nr_pages * page_size);
+
+	for (i = 0; i < nr_pages; i++) {
+		char expected = i == test_page ? 'B' : 'C';
+
+		test_private(t, i, expected, 'D');
+	}
+}
+
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 36/41] KVM: selftests: Reset shared memory after hole-punching

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

private_mem_conversions_test used to reset the shared memory that was used
for the test to an initial pattern at the end of each test iteration. Then,
it would punch out the pages, which would zero memory.

Without in-place conversion, the resetting would write shared memory, and
hole-punching will zero private memory, hence resetting the test to the
state at the beginning of the for loop.

With in-place conversion, resetting writes memory as shared, and
hole-punching zeroes the same physical memory, hence undoing the reset
done before the hole punch.

Move the resetting after the hole-punching, and reset the entire
PER_CPU_DATA_SIZE instead of just the tested range.

With in-place conversion, this zeroes and then resets the same physical
memory. Without in-place conversion, the private memory is zeroed, and the
shared memory is reset to init_p.

This is sufficient since at each test stage, the memory is assumed to start
as shared, and private memory is always assumed to start zeroed. Conversion
zeroes memory, so the future test stages will work as expected.

Fixes: 43f623f350ce1 ("KVM: selftests: Add x86-only selftest for private memory conversions")
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/x86/private_mem_conversions_test.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
index 861baff201e78..289ad10063fca 100644
--- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
@@ -202,15 +202,18 @@ static void guest_test_explicit_conversion(u64 base_gpa, bool do_fallocate)
 		guest_sync_shared(gpa, size, p3, p4);
 		memcmp_g(gpa, p4, size);
 
-		/* Reset the shared memory back to the initial pattern. */
-		memset((void *)gpa, init_p, size);
-
 		/*
 		 * Free (via PUNCH_HOLE) *all* private memory so that the next
 		 * iteration starts from a clean slate, e.g. with respect to
 		 * whether or not there are pages/folios in guest_mem.
 		 */
 		guest_map_shared(base_gpa, PER_CPU_DATA_SIZE, true);
+
+		/*
+		 * Hole-punching above zeroed private memory. Reset shared
+		 * memory in preparation for the next GUEST_STAGE.
+		 */
+		memset((void *)base_gpa, init_p, PER_CPU_DATA_SIZE);
 	}
 }
 

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 37/41] KVM: selftests: Provide function to look up guest_memfd details from gpa

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Introduce a new helper, kvm_gpa_to_guest_memfd(), to find the
guest_memfd-related details of a memory region that contains a given guest
physical address (GPA).

The function returns the file descriptor for the memfd, the offset into
the file that corresponds to the GPA, and the number of bytes remaining
in the region from that GPA.

kvm_gpa_to_guest_memfd() was factored out from vm_guest_mem_fallocate();
refactor vm_guest_mem_fallocate() to use the new helper.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h |  3 +++
 tools/testing/selftests/kvm/lib/kvm_util.c     | 37 ++++++++++++++++----------
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index b726e49a3cfcf..5f71eccf3565c 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -428,6 +428,9 @@ static inline void vm_enable_cap(struct kvm_vm *vm, u32 cap, u64 arg0)
 	vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap);
 }
 
+int kvm_gpa_to_guest_memfd(struct kvm_vm *vm, gpa_t gpa, off_t *fd_offset,
+			   size_t *nr_bytes);
+
 /*
  * KVM_SET_MEMORY_ATTRIBUTES{,2} overwrites _all_ attributes.  These
  * flows need significant enhancements to support multiple attributes.
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index ae0d7ff13f9f5..083717a11ff2d 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1334,27 +1334,20 @@ void vm_guest_mem_fallocate(struct kvm_vm *vm, u64 base, u64 size,
 			    bool punch_hole)
 {
 	const int mode = FALLOC_FL_KEEP_SIZE | (punch_hole ? FALLOC_FL_PUNCH_HOLE : 0);
-	struct userspace_mem_region *region;
 	u64 end = base + size;
-	gpa_t gpa, len;
 	off_t fd_offset;
-	int ret;
+	int fd, ret;
+	size_t len;
+	gpa_t gpa;
 
 	for (gpa = base; gpa < end; gpa += len) {
-		u64 offset;
-
-		region = userspace_mem_region_find(vm, gpa, gpa);
-		TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD,
-			    "Private memory region not found for GPA 0x%lx", gpa);
+		fd = kvm_gpa_to_guest_memfd(vm, gpa, &fd_offset, &len);
+		len = min(end - gpa, len);
 
-		offset = gpa - region->region.guest_phys_addr;
-		fd_offset = region->region.guest_memfd_offset + offset;
-		len = min_t(u64, end - gpa, region->region.memory_size - offset);
-
-		ret = fallocate(region->region.guest_memfd, mode, fd_offset, len);
+		ret = fallocate(fd, mode, fd_offset, len);
 		TEST_ASSERT(!ret, "fallocate() failed to %s at %lx (len = %lu), fd = %d, mode = %x, offset = %lx",
 			    punch_hole ? "punch hole" : "allocate", gpa, len,
-			    region->region.guest_memfd, mode, fd_offset);
+			    fd, mode, fd_offset);
 	}
 }
 
@@ -1691,6 +1684,22 @@ void *addr_gpa2alias(struct kvm_vm *vm, gpa_t gpa)
 	return (void *) ((uintptr_t) region->host_alias + offset);
 }
 
+int kvm_gpa_to_guest_memfd(struct kvm_vm *vm, gpa_t gpa, off_t *fd_offset,
+			   size_t *nr_bytes)
+{
+	struct userspace_mem_region *region;
+	gpa_t gpa_offset;
+
+	region = userspace_mem_region_find(vm, gpa, gpa);
+	TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD,
+		    "guest_memfd memory region not found for GPA 0x%lx", gpa);
+
+	gpa_offset = gpa - region->region.guest_phys_addr;
+	*fd_offset = region->region.guest_memfd_offset + gpa_offset;
+	*nr_bytes = region->region.memory_size - gpa_offset;
+	return region->region.guest_memfd;
+}
+
 /* Create an interrupt controller chip for the specified VM. */
 void vm_create_irqchip(struct kvm_vm *vm)
 {

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 38/41] KVM: selftests: Provide common function to set memory attributes

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Introduce vm_mem_set_memory_attributes(), which handles setting of memory
attributes for a range of guest physical addresses, regardless of whether
the attributes should be set via guest_memfd or via the memory attributes
at the VM level.

Refactor existing vm_mem_set_{shared,private} functions to use the new
function. Opportunistically update the size parameter to use size_t instead
of u64.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h | 46 +++++++++++++++++++-------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 5f71eccf3565c..628379c363d82 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -454,18 +454,6 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
 	vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr);
 }
 
-static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
-				      u64 size)
-{
-	vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE);
-}
-
-static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
-				     u64 size)
-{
-	vm_set_memory_attributes(vm, gpa, size, 0);
-}
-
 static inline int __gmem_set_memory_attributes(int fd, u64 offset,
 					       size_t size, u64 attributes,
 					       u64 *error_offset)
@@ -532,6 +520,40 @@ static inline void gmem_set_shared(int fd, u64 offset, size_t size)
 	gmem_set_memory_attributes(fd, offset, size, 0);
 }
 
+static inline void vm_mem_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
+						size_t size, u64 attrs)
+{
+	if (kvm_has_gmem_attributes) {
+		gpa_t end = gpa + size;
+		off_t fd_offset;
+		gpa_t addr;
+		size_t len;
+		int fd;
+
+		for (addr = gpa; addr < end; addr += len) {
+			fd = kvm_gpa_to_guest_memfd(vm, addr, &fd_offset, &len);
+			len = min(end - addr, len);
+
+			gmem_set_memory_attributes(fd, fd_offset, len, attrs);
+		}
+	} else {
+		vm_set_memory_attributes(vm, gpa, size, attrs);
+	}
+}
+
+static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
+				      size_t size)
+{
+	vm_mem_set_memory_attributes(vm, gpa, size,
+				     KVM_MEMORY_ATTRIBUTE_PRIVATE);
+}
+
+static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
+				     size_t size)
+{
+	vm_mem_set_memory_attributes(vm, gpa, size, 0);
+}
+
 void vm_guest_mem_fallocate(struct kvm_vm *vm, gpa_t gpa, u64 size,
 			    bool punch_hole);
 

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 39/41] KVM: selftests: Make TEST_EXPECT_SIGBUS thread-safe

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

The TEST_EXPECT_SIGBUS macro is not thread-safe as it uses a global
sigjmp_buf and installs a global SIGBUS signal handler. If multiple threads
execute the macro concurrently, they will race on installing the signal
handler and stomp on other threads' jump buffers, leading to incorrect test
behavior.

Make TEST_EXPECT_SIGBUS thread-safe with the following changes:

Share the KVM tests' global signal handler. sigaction() applies to all
threads; without sharing a global signal handler, one thread may have
removed the signal handler that another thread added, hence leading to
unexpected signals.

The alternative of layering signal handlers was considered, but calling
sigaction() within TEST_EXPECT_SIGBUS() necessarily creates a race. To
avoid adding new setup and teardown routines to do sigaction() and keep
usage of TEST_EXPECT_SIGBUS() simple, share the KVM tests' global signal
handler.

Opportunistically rename report_unexpected_signal to
catchall_signal_handler.

To continue to only expect SIGBUS within specific regions of code, use a
thread-specific variable, expecting_sigbus, to replace installing and
removing signal handlers.

Make the execution environment for the thread, sigjmp_buf, a
thread-specific variable.

As part of TEST_EXPECT_SIGBUS(), assert the prerequisite for this setup,
that the current signal handler is the catchall_signal_handler.

Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/test_util.h | 32 +++++++++++++------------
 tools/testing/selftests/kvm/lib/kvm_util.c      | 18 ++++++++++----
 tools/testing/selftests/kvm/lib/test_util.c     |  7 ------
 3 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index c6492a29ee901..825fad48ab452 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -82,21 +82,23 @@ do {									\
 	__builtin_unreachable(); \
 } while (0)
 
-extern sigjmp_buf expect_sigbus_jmpbuf;
-void expect_sigbus_handler(int signum);
-
-#define TEST_EXPECT_SIGBUS(action)						\
-do {										\
-	struct sigaction sa_old, sa_new = {					\
-		.sa_handler = expect_sigbus_handler,				\
-	};									\
-										\
-	sigaction(SIGBUS, &sa_new, &sa_old);					\
-	if (sigsetjmp(expect_sigbus_jmpbuf, 1) == 0) {				\
-		action;								\
-		TEST_FAIL("'%s' should have triggered SIGBUS", #action);	\
-	}									\
-	sigaction(SIGBUS, &sa_old, NULL);					\
+extern __thread sigjmp_buf expect_sigbus_jmpbuf;
+extern __thread volatile sig_atomic_t expecting_sigbus;
+extern void catchall_signal_handler(int signum);
+
+#define TEST_EXPECT_SIGBUS(action)					\
+do {									\
+	struct sigaction __sa = {};					\
+									\
+	TEST_ASSERT_EQ(sigaction(SIGBUS, NULL, &__sa), 0);		\
+	TEST_ASSERT_EQ(__sa.sa_handler, &catchall_signal_handler);	\
+									\
+	expecting_sigbus = true;					\
+	if (sigsetjmp(expect_sigbus_jmpbuf, 1) == 0) {			\
+		action;							\
+		TEST_FAIL("'%s' should have triggered SIGBUS", #action);\
+	}								\
+	expecting_sigbus = false;					\
 } while (0)
 
 size_t parse_size(const char *size);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 083717a11ff2d..ff70b4225f82e 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -2318,13 +2318,20 @@ __weak void kvm_selftest_arch_init(void)
 {
 }
 
-static void report_unexpected_signal(int signum)
+__thread sigjmp_buf expect_sigbus_jmpbuf;
+__thread volatile sig_atomic_t expecting_sigbus;
+
+void catchall_signal_handler(int signum)
 {
+	switch (signum) {
+	case SIGBUS: {
+		if (expecting_sigbus)
+			siglongjmp(expect_sigbus_jmpbuf, 1);
+
+		TEST_FAIL("Unexpected SIGBUS (%d)\n", signum);
+	}
 #define KVM_CASE_SIGNUM(sig)					\
 	case sig: TEST_FAIL("Unexpected " #sig " (%d)\n", signum)
-
-	switch (signum) {
-	KVM_CASE_SIGNUM(SIGBUS);
 	KVM_CASE_SIGNUM(SIGSEGV);
 	KVM_CASE_SIGNUM(SIGILL);
 	KVM_CASE_SIGNUM(SIGFPE);
@@ -2336,12 +2343,13 @@ static void report_unexpected_signal(int signum)
 void __attribute((constructor)) kvm_selftest_init(void)
 {
 	struct sigaction sig_sa = {
-		.sa_handler = report_unexpected_signal,
+		.sa_handler = catchall_signal_handler,
 	};
 
 	/* Tell stdout not to buffer its content. */
 	setbuf(stdout, NULL);
 
+	expecting_sigbus = false;
 	sigaction(SIGBUS, &sig_sa, NULL);
 	sigaction(SIGSEGV, &sig_sa, NULL);
 	sigaction(SIGILL, &sig_sa, NULL);
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index 6b00ab11f3c02..36e08d815758f 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -19,13 +19,6 @@
 #include "test_util.h"
 #include "kvm_syscalls.h"
 
-sigjmp_buf expect_sigbus_jmpbuf;
-
-void __attribute__((used)) expect_sigbus_handler(int signum)
-{
-	siglongjmp(expect_sigbus_jmpbuf, 1);
-}
-
 /*
  * Random number generator that is usable from guest code. This is the
  * Park-Miller LCG using standard constants.

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 40/41] KVM: selftests: Update private_mem_conversions_test to mmap() guest_memfd

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@google.com>

Update the private memory conversions selftest to also test conversions
that are done "in-place" via per-guest_memfd memory attributes. In-place
conversions require the host to be able to mmap() the guest_memfd so that
the host and guest can share the same backing physical memory.

This includes several updates, that are conditioned on the system
supporting per-guest_memfd attributes (kvm_has_gmem_attributes):

1. Set up guest_memfd requesting MMAP and INIT_SHARED.

2. With in-place conversions, the host's mapping points directly to the
   guest's memory. When the guest converts a region to private, host access
   to that region is blocked. Update the test to expect a SIGBUS when
   attempting to access the host virtual address (HVA) of private memory.

3. Use vm_mem_set_memory_attributes(), which chooses how to set memory
   attributes based on whether kvm_has_gmem_attributes.

Restrict the test to using VM_MEM_SRC_SHMEM because guest_memfd's required
mmap() flags and page sizes happens to align with those of
VM_MEM_SRC_SHMEM. As long as VM_MEM_SRC_SHMEM is used for src_type,
vm_mem_add() works as intended.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../kvm/x86/private_mem_conversions_test.c         | 44 ++++++++++++++++++----
 1 file changed, 36 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
index 289ad10063fca..4308c67952310 100644
--- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
@@ -306,9 +306,12 @@ static void handle_exit_hypercall(struct kvm_vcpu *vcpu)
 	if (do_fallocate)
 		vm_guest_mem_fallocate(vm, gpa, size, map_shared);
 
-	if (set_attributes)
-		vm_set_memory_attributes(vm, gpa, size,
-					 map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE);
+	if (set_attributes) {
+		u64 attrs = map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE;
+
+		vm_mem_set_memory_attributes(vm, gpa, size, attrs);
+	}
+
 	run->hypercall.ret = 0;
 }
 
@@ -352,8 +355,20 @@ static void *__test_mem_conversions(void *__vcpu)
 				size_t nr_bytes = min_t(size_t, vm->page_size, size - i);
 				u8 *hva = addr_gpa2hva(vm, gpa + i);
 
-				/* In all cases, the host should observe the shared data. */
-				memcmp_h(hva, gpa + i, uc.args[3], nr_bytes);
+				/*
+				 * When using per-guest_memfd memory attributes,
+				 * i.e. in-place conversion, host accesses will
+				 * point at guest memory and should SIGBUS when
+				 * guest memory is private.  When using per-VM
+				 * attributes, i.e. separate backing for shared
+				 * vs. private, the host should always observe
+				 * the shared data.
+				 */
+				if (kvm_has_gmem_attributes &&
+				    uc.args[0] == SYNC_PRIVATE)
+					TEST_EXPECT_SIGBUS(READ_ONCE(*hva));
+				else
+					memcmp_h(hva, gpa + i, uc.args[3], nr_bytes);
 
 				/* For shared, write the new pattern to guest memory. */
 				if (uc.args[0] == SYNC_SHARED)
@@ -382,6 +397,7 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_v
 	const size_t slot_size = memfd_size / nr_memslots;
 	struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
 	pthread_t threads[KVM_MAX_VCPUS];
+	u64 gmem_flags;
 	struct kvm_vm *vm;
 	int memfd, i;
 
@@ -397,12 +413,17 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_v
 
 	vm_enable_cap(vm, KVM_CAP_EXIT_HYPERCALL, (1 << KVM_HC_MAP_GPA_RANGE));
 
-	memfd = vm_create_guest_memfd(vm, memfd_size, 0);
+	if (kvm_has_gmem_attributes)
+		gmem_flags = GUEST_MEMFD_FLAG_MMAP | GUEST_MEMFD_FLAG_INIT_SHARED;
+	else
+		gmem_flags = 0;
+
+	memfd = vm_create_guest_memfd(vm, memfd_size, gmem_flags);
 
 	for (i = 0; i < nr_memslots; i++)
 		vm_mem_add(vm, src_type, BASE_DATA_GPA + slot_size * i,
 			   BASE_DATA_SLOT + i, slot_size / vm->page_size,
-			   KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, 0);
+			   KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, gmem_flags);
 
 	for (i = 0; i < nr_vcpus; i++) {
 		gpa_t gpa =  BASE_DATA_GPA + i * per_cpu_size;
@@ -452,17 +473,24 @@ static void usage(const char *cmd)
 
 int main(int argc, char *argv[])
 {
-	enum vm_mem_backing_src_type src_type = DEFAULT_VM_MEM_SRC;
+	enum vm_mem_backing_src_type src_type;
 	u32 nr_memslots = 1;
 	u32 nr_vcpus = 1;
 	int opt;
 
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
 
+	src_type = kvm_has_gmem_attributes ? VM_MEM_SRC_SHMEM :
+					     DEFAULT_VM_MEM_SRC;
+
 	while ((opt = getopt(argc, argv, "hm:s:n:")) != -1) {
 		switch (opt) {
 		case 's':
 			src_type = parse_backing_src_type(optarg);
+			TEST_ASSERT(!kvm_has_gmem_attributes ||
+				    src_type == VM_MEM_SRC_SHMEM,
+				    "Testing in-place conversions, only %s mem_type supported\n",
+				    vm_mem_backing_src_alias(VM_MEM_SRC_SHMEM)->name);
 			break;
 		case 'n':
 			nr_vcpus = atoi_positive("nr_vcpus", optarg);

-- 
2.55.0.508.g3f0d502094-goog

[PATCH v9 41/41] KVM: selftests: Update private memory exits test to work with per-gmem attributes

[Ackerley Tng via B4 Relay]

From: Sean Christopherson <seanjc@google.com>

Skip setting memory to private in the private memory exits test when using
per-gmem memory attributes, as memory is initialized to private by default
for guest_memfd, and using vm_mem_set_private() on a guest_memfd instance
requires creating guest_memfd with GUEST_MEMFD_FLAG_MMAP (which is totally
doable, but would need to be conditional and is ultimately unnecessary).

Expect an emulated MMIO instead of a memory fault exit when attributes are
per-gmem, as deleting the memslot effectively drops the private status,
i.e. the GPA becomes shared and thus supports emulated MMIO.

Skip the "memslot not private" test entirely, as private vs. shared state
for x86 software-protected VMs comes from the memory attributes themselves,
and so when doing in-place conversions there can never be a disconnect
between the expected and actual states.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../selftests/kvm/x86/private_mem_kvm_exits_test.c | 36 ++++++++++++++++++----
 1 file changed, 30 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c b/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c
index 10db9fe6d9063..70ed16066c63e 100644
--- a/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c
+++ b/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c
@@ -62,8 +62,9 @@ static void test_private_access_memslot_deleted(void)
 
 	virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES);
 
-	/* Request to access page privately */
-	vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
+	/* Request to access page privately. */
+	if (!kvm_has_gmem_attributes)
+		vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
 
 	pthread_create(&vm_thread, NULL,
 		       (void *(*)(void *))run_vcpu_get_exit_reason,
@@ -74,10 +75,26 @@ static void test_private_access_memslot_deleted(void)
 	pthread_join(vm_thread, &thread_return);
 	exit_reason = (u32)(u64)thread_return;
 
-	TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
-	TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
-	TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
-	TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
+	/*
+	 * If attributes are tracked per-gmem, deleting the memslot that points
+	 * at the gmem instance effectively makes the memory shared, and so the
+	 * read should trigger emulated MMIO.
+	 *
+	 * If attributes are tracked per-VM, deleting the memslot shouldn't
+	 * affect the private attribute, and so KVM should generate a memory
+	 * fault exit (emulated MMIO on private GPAs is disallowed).
+	 */
+	if (kvm_has_gmem_attributes) {
+		TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MMIO);
+		TEST_ASSERT_EQ(vcpu->run->mmio.phys_addr, EXITS_TEST_GPA);
+		TEST_ASSERT_EQ(vcpu->run->mmio.len, sizeof(u64));
+		TEST_ASSERT_EQ(vcpu->run->mmio.is_write, false);
+	} else {
+		TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
+		TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
+		TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
+		TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
+	}
 
 	kvm_vm_free(vm);
 }
@@ -88,6 +105,13 @@ static void test_private_access_memslot_not_private(void)
 	struct kvm_vcpu *vcpu;
 	u32 exit_reason;
 
+	/*
+	 * Accessing non-private memory as private with a software-protected VM
+	 * isn't possible when doing in-place conversions.
+	 */
+	if (kvm_has_gmem_attributes)
+		return;
+
 	vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu,
 					   guest_repeatedly_read);
 

-- 
2.55.0.508.g3f0d502094-goog