[PATCH V5 03/12] x86/hyperv: Add new hvcall guest address host visibility support

Tianyu Lan
2021-09-14T13:39:38Z

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Add new hvcall guest address host visibility support to mark
memory visible to host. Call it inside set_memory_decrypted
/encrypted(). Add HYPERVISOR feature check in the
hv_is_isolation_supported() to optimize in non-virtualization
environment.

Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v4:
* Fix typo in the comment
* Make hv_mark_gpa_visibility() to be a static function
* Merge __hv_set_mem_host_visibility() and hv_set_mem_host_visibility()

Change since v3:
* Fix error code handle in the __hv_set_mem_host_visibility().
* Move HvCallModifySparseGpaPageHostVisibility near to enum
hv_mem_host_visibility.

Change since v2:
* Rework __set_memory_enc_dec() and call Hyper-V and AMD function
according to platform check.

Change since v1:
* Use new staic call x86_set_memory_enc to avoid add Hyper-V
specific check in the set_memory code.
---
arch/x86/hyperv/Makefile | 2 +-
arch/x86/hyperv/hv_init.c | 6 ++
arch/x86/hyperv/ivm.c | 105 +++++++++++++++++++++++++++++
arch/x86/include/asm/hyperv-tlfs.h | 17 +++++
arch/x86/include/asm/mshyperv.h | 2 +-
arch/x86/mm/pat/set_memory.c | 19 ++++--
include/asm-generic/hyperv-tlfs.h | 1 +
include/asm-generic/mshyperv.h | 1 +
8 files changed, 146 insertions(+), 7 deletions(-)
create mode 100644 arch/x86/hyperv/ivm.c

diff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile
index 48e2c51464e8..5d2de10809ae 100644
--- a/arch/x86/hyperv/Makefile
+++ b/arch/x86/hyperv/Makefile
@@ -1,5 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
-obj-y := hv_init.o mmu.o nested.o irqdomain.o
+obj-y := hv_init.o mmu.o nested.o irqdomain.o ivm.o
obj-$(CONFIG_X86_64) += hv_apic.o hv_proc.o

ifdef CONFIG_X86_64
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index a7e922755ad1..d57df6825527 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -603,6 +603,12 @@ EXPORT_SYMBOL_GPL(hv_get_isolation_type);

bool hv_is_isolation_supported(void)
{
+ if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
+ return false;
+
+ if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
+ return false;
+
return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
}

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
new file mode 100644
index 000000000000..79e7fb83472a
--- /dev/null
+++ b/arch/x86/hyperv/ivm.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hyper-V Isolation VM interface with paravisor and hypervisor
+ *
+ * Author:
+ * Tianyu Lan <Tianyu.Lan@microsoft.com>
+ */
+
+#include <linux/hyperv.h>
+#include <linux/types.h>
+#include <linux/bitfield.h>
+#include <linux/slab.h>
+#include <asm/io.h>
+#include <asm/mshyperv.h>
+
+/*
+ * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
+ *
+ * In Isolation VM, all guest memory is encrypted from host and guest
+ * needs to set memory visible to host via hvcall before sharing memory
+ * with host.
+ */
+static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
+ enum hv_mem_host_visibility visibility)
+{
+ struct hv_gpa_range_for_visibility **input_pcpu, *input;
+ u16 pages_processed;
+ u64 hv_status;
+ unsigned long flags;
+
+ /* no-op if partition isolation is not enabled */
+ if (!hv_is_isolation_supported())
+ return 0;
+
+ if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
+ pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
+ HV_MAX_MODIFY_GPA_REP_COUNT);
+ return -EINVAL;
+ }
+
+ local_irq_save(flags);
+ input_pcpu = (struct hv_gpa_range_for_visibility **)
+ this_cpu_ptr(hyperv_pcpu_input_arg);
+ input = *input_pcpu;
+ if (unlikely(!input)) {
+ local_irq_restore(flags);
+ return -EINVAL;
+ }
+
+ input->partition_id = HV_PARTITION_ID_SELF;
+ input->host_visibility = visibility;
+ input->reserved0 = 0;
+ input->reserved1 = 0;
+ memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
+ hv_status = hv_do_rep_hypercall(
+ HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
+ 0, input, &pages_processed);
+ local_irq_restore(flags);
+
+ if (hv_result_success(hv_status))
+ return 0;
+ else
+ return -EFAULT;
+}
+
+/*
+ * hv_set_mem_host_visibility - Set specified memory visible to host.
+ *
+ * In Isolation VM, all guest memory is encrypted from host and guest
+ * needs to set memory visible to host via hvcall before sharing memory
+ * with host. This function works as wrap of hv_mark_gpa_visibility()
+ * with memory base and size.
+ */
+int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visible)
+{
+ enum hv_mem_host_visibility visibility = visible ?
+ VMBUS_PAGE_VISIBLE_READ_WRITE : VMBUS_PAGE_NOT_VISIBLE;
+ u64 *pfn_array;
+ int ret = 0;
+ int i, pfn;
+
+ if (!hv_is_isolation_supported() || !hv_hypercall_pg)
+ return 0;
+
+ pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+ if (!pfn_array)
+ return -ENOMEM;
+
+ for (i = 0, pfn = 0; i < pagecount; i++) {
+ pfn_array[pfn] = virt_to_hvpfn((void *)kbuffer + i * HV_HYP_PAGE_SIZE);
+ pfn++;
+
+ if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
+ ret = hv_mark_gpa_visibility(pfn, pfn_array,
+ visibility);
+ if (ret)
+ goto err_free_pfn_array;
+ pfn = 0;
+ }
+ }
+
+ err_free_pfn_array:
+ kfree(pfn_array);
+ return ret;
+}
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 2322d6bd5883..381e88122a5f 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -276,6 +276,23 @@ enum hv_isolation_type {
#define HV_X64_MSR_TIME_REF_COUNT HV_REGISTER_TIME_REF_COUNT
#define HV_X64_MSR_REFERENCE_TSC HV_REGISTER_REFERENCE_TSC

+/* Hyper-V memory host visibility */
+enum hv_mem_host_visibility {
+ VMBUS_PAGE_NOT_VISIBLE = 0,
+ VMBUS_PAGE_VISIBLE_READ_ONLY = 1,
+ VMBUS_PAGE_VISIBLE_READ_WRITE = 3
+};
+
+/* HvCallModifySparseGpaPageHostVisibility hypercall */
+#define HV_MAX_MODIFY_GPA_REP_COUNT ((PAGE_SIZE / sizeof(u64)) - 2)
+struct hv_gpa_range_for_visibility {
+ u64 partition_id;
+ u32 host_visibility:2;
+ u32 reserved0:30;
+ u32 reserved1;
+ u64 gpa_page_list[HV_MAX_MODIFY_GPA_REP_COUNT];
+} __packed;
+
/*
* Declare the MSR used to setup pages used to communicate with the hypervisor.
*/
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 37739a277ac6..ede440f9a1e2 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -192,7 +192,7 @@ struct irq_domain *hv_create_pci_msi_domain(void);
int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector,
struct hv_interrupt_entry *entry);
int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
-
+int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible);
#else /* CONFIG_HYPERV */
static inline void hyperv_init(void) {}
static inline void hyperv_setup_mmu_ops(void) {}
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index ad8a5c586a35..1e4a0882820a 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -29,6 +29,8 @@
#include <asm/proto.h>
#include <asm/memtype.h>
#include <asm/set_memory.h>
+#include <asm/hyperv-tlfs.h>
+#include <asm/mshyperv.h>

#include "../mm_internal.h"

@@ -1980,15 +1982,11 @@ int set_memory_global(unsigned long addr, int numpages)
__pgprot(_PAGE_GLOBAL), 0);
}

-static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
+static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
{
struct cpa_data cpa;
int ret;

- /* Nothing to do if memory encryption is not active */
- if (!mem_encrypt_active())
- return 0;
-
/* Should not be working on unaligned addresses */
if (WARN_ONCE(addr & ~PAGE_MASK, "misaligned address: %#lx\n", addr))
addr &= PAGE_MASK;
@@ -2023,6 +2021,17 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
return ret;
}

+static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
+{
+ if (hv_is_isolation_supported())
+ return hv_set_mem_host_visibility(addr, numpages, !enc);
+
+ if (mem_encrypt_active())
+ return __set_memory_enc_pgtable(addr, numpages, enc);
+
+ return 0;
+}
+
int set_memory_encrypted(unsigned long addr, int numpages)
{
return __set_memory_enc_dec(addr, numpages, true);
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index 56348a541c50..8ed6733d5146 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -158,6 +158,7 @@ struct ms_hyperv_tsc_page {
#define HVCALL_RETARGET_INTERRUPT 0x007e
#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af
#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0
+#define HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db

/* Extended hypercalls */
#define HV_EXT_CALL_QUERY_CAPABILITIES 0x8001
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index e04efb87fee5..cb529c85c0ad 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -254,6 +254,7 @@ bool hv_query_ext_cap(u64 cap_query);
static inline bool hv_is_hyperv_initialized(void) { return false; }
static inline bool hv_is_hibernation_supported(void) { return false; }
static inline void hyperv_cleanup(void) {}
+static inline bool hv_is_isolation_supported(void) { return false; }
#endif /* CONFIG_HYPERV */

#endif
--
2.25.1