From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Add two PFERR codes to designate that the page fault is private and that
it requires looking up memory attributes. The vendor kvm page fault
handler should set PFERR_GUEST_ENC_MASK bit based on their fault
information. It may or may not use the hardware value directly or
parse the hardware value to set the bit.
For KVM_X86_PROTECTED_VM, ask memory attributes for the fault privateness.
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
Changes v3 -> v4:
- rename back struct kvm_page_fault::private => is_private
- catch up rename: KVM_X86_PROTECTED_VM => KVM_X86_SW_PROTECTED_VM
Changes v2 -> v3:
- Revive PFERR_GUEST_ENC_MASK
- rename struct kvm_page_fault::is_private => private
- Add check KVM_X86_PROTECTED_VM
Changes v1 -> v2:
- Introduced fault type and replaced is_private with fault_type.
- Add kvm_get_fault_type() to encapsulate the difference.
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/mmu/mmu.c | 8 ++++++--
arch/x86/kvm/mmu/mmu_internal.h | 14 +++++++++++++-
3 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2c9350aa0da4..ab7d080bf544 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -255,6 +255,7 @@ enum x86_intercept_stage;
#define PFERR_SGX_BIT 15
#define PFERR_GUEST_FINAL_BIT 32
#define PFERR_GUEST_PAGE_BIT 33
+#define PFERR_GUEST_ENC_BIT 34
#define PFERR_IMPLICIT_ACCESS_BIT 48
#define PFERR_PRESENT_MASK BIT(PFERR_PRESENT_BIT)
@@ -266,6 +267,7 @@ enum x86_intercept_stage;
#define PFERR_SGX_MASK BIT(PFERR_SGX_BIT)
#define PFERR_GUEST_FINAL_MASK BIT_ULL(PFERR_GUEST_FINAL_BIT)
#define PFERR_GUEST_PAGE_MASK BIT_ULL(PFERR_GUEST_PAGE_BIT)
+#define PFERR_GUEST_ENC_MASK BIT_ULL(PFERR_GUEST_ENC_BIT)
#define PFERR_IMPLICIT_ACCESS BIT_ULL(PFERR_IMPLICIT_ACCESS_BIT)
#define PFERR_NESTED_GUEST_PAGE (PFERR_GUEST_PAGE_MASK | \
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a2fe091e327a..d2ebe26fb822 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4399,8 +4399,12 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
return RET_PF_EMULATE;
}
- if (fault->is_private != kvm_mem_is_private(vcpu->kvm, fault->gfn))
- return kvm_do_memory_fault_exit(vcpu, fault);
+ if (fault->is_private != kvm_mem_is_private(vcpu->kvm, fault->gfn)) {
+ if (vcpu->kvm->arch.vm_type == KVM_X86_SW_PROTECTED_VM)
+ return RET_PF_RETRY;
+ else
+ return kvm_do_memory_fault_exit(vcpu, fault);
+ }
if (fault->is_private)
return kvm_faultin_pfn_private(vcpu, fault);
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 7f9ec1e5b136..4f8f83546c37 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -282,6 +282,18 @@ enum {
RET_PF_SPURIOUS,
};
+static inline bool kvm_is_fault_private(struct kvm *kvm, gpa_t gpa, u64 error_code)
+{
+ /*
+ * This is racy with mmu_seq. If we hit a race, it would result in a
+ * spurious KVM_EXIT_MEMORY_FAULT.
+ */
+ if (kvm->arch.vm_type == KVM_X86_SW_PROTECTED_VM)
+ return kvm_mem_is_private(kvm, gpa_to_gfn(gpa));
+
+ return error_code & PFERR_GUEST_ENC_MASK;
+}
+
static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
u64 err, bool prefetch, int *emulation_type)
{
@@ -295,13 +307,13 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
.user = err & PFERR_USER_MASK,
.prefetch = prefetch,
.is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault),
+ .is_private = kvm_is_fault_private(vcpu->kvm, cr2_or_gpa, err),
.nx_huge_page_workaround_enabled =
is_nx_huge_page_enabled(vcpu->kvm),
.max_level = KVM_MAX_HUGEPAGE_LEVEL,
.req_level = PG_LEVEL_4K,
.goal_level = PG_LEVEL_4K,
- .is_private = kvm_mem_is_private(vcpu->kvm, cr2_or_gpa >> PAGE_SHIFT),
};
int r;
--
2.25.1
