[PATCH Part2 RFC v2 27/37] KVM: X86: Introduce kvm_mmu_map_tdp_page() for use by SEV
From: Brijesh Singh <hidden>
Date: 2021-04-30 12:41:03
Also in:
lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Introduce a helper to directly fault-in a TDP page without going through the full page fault path. This allows SEV-SNP to build the netsted page table while handling the page state change VMGEXIT. A guest may issue a page state change VMGEXIT before accessing the page. Create a fault so that VMGEXIT handler can get the TDP page level and keep the TDP and RMP page level in sync. Signed-off-by: Brijesh Singh <redacted> --- arch/x86/kvm/mmu.h | 2 ++ arch/x86/kvm/mmu/mmu.c | 20 ++++++++++++++++++++ 2 files changed, 22 insertions(+)
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 88d0ed5225a4..005ce139c97d 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h@@ -114,6 +114,8 @@ static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu) int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, bool prefault); +int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, int max_level); + static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u32 err, bool prefault) {
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index fe2c5a704a16..d150201cf10c 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c@@ -3842,6 +3842,26 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, max_level, true); } +int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, int max_level) +{ + int r; + + /* + * Loop on the page fault path to handle the case where an mmu_notifier + * invalidation triggers RET_PF_RETRY. In the normal page fault path, + * KVM needs to resume the guest in case the invalidation changed any + * of the page fault properties, i.e. the gpa or error code. For this + * path, the gpa and error code are fixed by the caller, and the caller + * expects failure if and only if the page fault can't be fixed. + */ + do { + r = direct_page_fault(vcpu, gpa, error_code, false, max_level, true); + } while (r == RET_PF_RETRY); + + return r; +} +EXPORT_SYMBOL_GPL(kvm_mmu_map_tdp_page); + static void nonpaging_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context) {
--
2.17.1