[PATCH v10 5/8] KVM: PPC: Handle memory plug/unplug to secure VM

Bharata B Rao
2019-11-04T04:29:57Z

Register the new memslot with UV during plug and unregister
the memslot during unplug. In addition, release all the
device pages during unplug.

Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
[Added skip_page_out arg to kvmppc_uvmem_drop_pages()]
---
arch/powerpc/include/asm/kvm_book3s_uvmem.h | 6 ++++
arch/powerpc/include/asm/ultravisor-api.h | 1 +
arch/powerpc/include/asm/ultravisor.h | 5 +++
arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 ++
arch/powerpc/kvm/book3s_hv.c | 24 +++++++++++++
arch/powerpc/kvm/book3s_hv_uvmem.c | 37 +++++++++++++++++++++
6 files changed, 76 insertions(+)

diff --git a/arch/powerpc/include/asm/kvm_book3s_uvmem.h b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
index 3033a9585b43..3cf8425b9838 100644
--- a/arch/powerpc/include/asm/kvm_book3s_uvmem.h
+++ b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
@@ -19,6 +19,8 @@ unsigned long kvmppc_h_svm_page_out(struct kvm *kvm,
unsigned long kvmppc_h_svm_init_start(struct kvm *kvm);
unsigned long kvmppc_h_svm_init_done(struct kvm *kvm);
int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn);
+void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
+ struct kvm *kvm, bool skip_page_out);
#else
static inline int kvmppc_uvmem_init(void)
{
@@ -64,5 +66,9 @@ static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
{
return -EFAULT;
}
+
+static inline void
+kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
+ struct kvm *kvm, bool skip_page_out) { }
#endif /* CONFIG_PPC_UV */
#endif /* __ASM_KVM_BOOK3S_UVMEM_H__ */
diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
index e774274ab30e..4b0d044caa2a 100644
--- a/arch/powerpc/include/asm/ultravisor-api.h
+++ b/arch/powerpc/include/asm/ultravisor-api.h
@@ -27,6 +27,7 @@
#define UV_RETURN 0xF11C
#define UV_ESM 0xF110
#define UV_REGISTER_MEM_SLOT 0xF120
+#define UV_UNREGISTER_MEM_SLOT 0xF124
#define UV_PAGE_IN 0xF128
#define UV_PAGE_OUT 0xF12C
#define UV_SHARE_PAGE 0xF130
diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h
index 40cc8bace654..b8e59b7b4ac8 100644
--- a/arch/powerpc/include/asm/ultravisor.h
+++ b/arch/powerpc/include/asm/ultravisor.h
@@ -67,6 +67,11 @@ static inline int uv_register_mem_slot(u64 lpid, u64 start_gpa, u64 size,
size, flags, slotid);
}

+static inline int uv_unregister_mem_slot(u64 lpid, u64 slotid)
+{
+ return ucall_norets(UV_UNREGISTER_MEM_SLOT, lpid, slotid);
+}
+
static inline int uv_page_inval(u64 lpid, u64 gpa, u64 page_shift)
{
return ucall_norets(UV_PAGE_INVAL, lpid, gpa, page_shift);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 4aec55a0ebc7..ee70bfc28c82 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -1101,6 +1101,9 @@ void kvmppc_radix_flush_memslot(struct kvm *kvm,
unsigned long gpa;
unsigned int shift;

+ if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START)
+ kvmppc_uvmem_drop_pages(memslot, kvm, true);
+
if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE)
return;

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 80e84277d11f..cb7ae1e9e4f2 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -74,6 +74,7 @@
#include <asm/hw_breakpoint.h>
#include <asm/kvm_host.h>
#include <asm/kvm_book3s_uvmem.h>
+#include <asm/ultravisor.h>

#include "book3s.h"

@@ -4532,6 +4533,29 @@ static void kvmppc_core_commit_memory_region_hv(struct kvm *kvm,
if (change = KVM_MR_FLAGS_ONLY && kvm_is_radix(kvm) &&
((new->flags ^ old->flags) & KVM_MEM_LOG_DIRTY_PAGES))
kvmppc_radix_flush_memslot(kvm, old);
+ /*
+ * If UV hasn't yet called H_SVM_INIT_START, don't register memslots.
+ */
+ if (!kvm->arch.secure_guest)
+ return;
+
+ switch (change) {
+ case KVM_MR_CREATE:
+ if (kvmppc_uvmem_slot_init(kvm, new))
+ return;
+ uv_register_mem_slot(kvm->arch.lpid,
+ new->base_gfn << PAGE_SHIFT,
+ new->npages * PAGE_SIZE,
+ 0, new->id);
+ break;
+ case KVM_MR_DELETE:
+ uv_unregister_mem_slot(kvm->arch.lpid, old->id);
+ kvmppc_uvmem_slot_free(kvm, old);
+ break;
+ default:
+ /* TODO: Handle KVM_MR_MOVE */
+ break;
+ }
}

/*
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 6dbb11ee4bc0..6f26a0351a31 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -241,6 +241,43 @@ unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
return H_SUCCESS;
}

+/*
+ * Drop device pages that we maintain for the secure guest
+ *
+ * We first mark the pages to be skipped from UV_PAGE_OUT when there
+ * is HV side fault on these pages. Next we *get* these pages, forcing
+ * fault on them, do fault time migration to replace the device PTEs in
+ * QEMU page table with normal PTEs from newly allocated pages.
+ */
+void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
+ struct kvm *kvm, bool skip_page_out)
+{
+ int i;
+ struct kvmppc_uvmem_page_pvt *pvt;
+ unsigned long pfn, uvmem_pfn;
+ unsigned long gfn = free->base_gfn;
+
+ for (i = free->npages; i; --i, ++gfn) {
+ struct page *uvmem_page;
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+ if (!kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
+ mutex_unlock(&kvm->arch.uvmem_lock);
+ continue;
+ }
+
+ uvmem_page = pfn_to_page(uvmem_pfn);
+ pvt = uvmem_page->zone_device_data;
+ pvt->skip_page_out = skip_page_out;
+ mutex_unlock(&kvm->arch.uvmem_lock);
+
+ pfn = gfn_to_pfn(kvm, gfn);
+ if (is_error_noslot_pfn(pfn))
+ continue;
+ kvm_release_pfn_clean(pfn);
+ }
+}
+
/*
* Get a free device PFN from the pool
*
--
2.21.0