| Message ID | ae4475bc740eb0b9d031a76412b0117339794139.1655761627.git.ashish.kalra@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) | expand |
s/X86/x86/ On Mon, Jun 20, 2022 at 11:08:57PM +0000, Ashish Kalra wrote: > From: Brijesh Singh <brijesh.singh@amd.com> > > When running an SEV-SNP VM, the sPA used to index the RMP entry is > obtained through the NPT translation (gva->gpa->spa). The NPT page > level is checked against the page level programmed in the RMP entry. > If the page level does not match, then it will cause a nested page > fault with the RMP bit set to indicate the RMP violation. > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > arch/x86/include/asm/kvm-x86-ops.h | 1 + > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/mmu/mmu.c | 5 ++++ > arch/x86/kvm/svm/sev.c | 46 ++++++++++++++++++++++++++++++ > arch/x86/kvm/svm/svm.c | 1 + > arch/x86/kvm/svm/svm.h | 1 + > 6 files changed, 55 insertions(+) > > diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h > index a66292dae698..e0068e702692 100644 > --- a/arch/x86/include/asm/kvm-x86-ops.h > +++ b/arch/x86/include/asm/kvm-x86-ops.h > @@ -129,6 +129,7 @@ KVM_X86_OP(complete_emulated_msr) > KVM_X86_OP(vcpu_deliver_sipi_vector) > KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons); > KVM_X86_OP(alloc_apic_backing_page) > +KVM_X86_OP_OPTIONAL(rmp_page_level_adjust) > > #undef KVM_X86_OP > #undef KVM_X86_OP_OPTIONAL > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 0205e2944067..2748c69609e3 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1514,6 +1514,7 @@ struct kvm_x86_ops { > unsigned long (*vcpu_get_apicv_inhibit_reasons)(struct kvm_vcpu *vcpu); > > void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu); > + void (*rmp_page_level_adjust)(struct kvm *kvm, kvm_pfn_t pfn, int *level); > }; > > struct kvm_x86_nested_ops { > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index c623019929a7..997318ecebd1 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -43,6 +43,7 @@ > #include <linux/hash.h> > #include <linux/kern_levels.h> > #include <linux/kthread.h> > +#include <linux/sev.h> > > #include <asm/page.h> > #include <asm/memtype.h> > @@ -2824,6 +2825,10 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, > if (unlikely(!pte)) > return PG_LEVEL_4K; > > + /* Adjust the page level based on the SEV-SNP RMP page level. */ > + if (kvm_x86_ops.rmp_page_level_adjust) > + static_call(kvm_x86_rmp_page_level_adjust)(kvm, pfn, &level); > + > return level; > } > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index a5b90469683f..91d3d24e60d2 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -3597,3 +3597,49 @@ struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu) > > return pfn_to_page(pfn); > } > + > +static bool is_pfn_range_shared(kvm_pfn_t start, kvm_pfn_t end) > +{ > + int level; > + > + while (end > start) { > + if (snp_lookup_rmpentry(start, &level) != 0) > + return false; > + start++; > + } > + > + return true; > +} > + > +void sev_rmp_page_level_adjust(struct kvm *kvm, kvm_pfn_t pfn, int *level) Would not do harm to document this, given that it is not a static fuction. > +{ > + int rmp_level, assigned; > + > + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) > + return; > + > + assigned = snp_lookup_rmpentry(pfn, &rmp_level); > + if (unlikely(assigned < 0)) > + return; > + > + if (!assigned) { > + /* > + * If all the pages are shared then no need to keep the RMP > + * and NPT in sync. > + */ > + pfn = pfn & ~(PTRS_PER_PMD - 1); > + if (is_pfn_range_shared(pfn, pfn + PTRS_PER_PMD)) > + return; > + } > + > + /* > + * The hardware installs 2MB TLB entries to access to 1GB pages, > + * therefore allow NPT to use 1GB pages when pfn was added as 2MB > + * in the RMP table. > + */ > + if (rmp_level == PG_LEVEL_2M && (*level == PG_LEVEL_1G)) > + return; > + > + /* Adjust the level to keep the NPT and RMP in sync */ > + *level = min_t(size_t, *level, rmp_level); > +} > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index b4bd64f94d3a..18e2cd4d9559 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -4734,6 +4734,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { > .vcpu_get_apicv_inhibit_reasons = avic_vcpu_get_apicv_inhibit_reasons, > > .alloc_apic_backing_page = svm_alloc_apic_backing_page, > + .rmp_page_level_adjust = sev_rmp_page_level_adjust, > }; > > /* > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 71c011af098e..7782312a1cda 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -673,6 +673,7 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector); > void sev_es_prepare_switch_to_guest(struct sev_es_save_area *hostsa); > void sev_es_unmap_ghcb(struct vcpu_svm *svm); > struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu); > +void sev_rmp_page_level_adjust(struct kvm *kvm, kvm_pfn_t pfn, int *level); > > /* vmenter.S */ > > -- > 2.25.1 > BR, Jarkko
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index a66292dae698..e0068e702692 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -129,6 +129,7 @@ KVM_X86_OP(complete_emulated_msr) KVM_X86_OP(vcpu_deliver_sipi_vector) KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons); KVM_X86_OP(alloc_apic_backing_page) +KVM_X86_OP_OPTIONAL(rmp_page_level_adjust) #undef KVM_X86_OP #undef KVM_X86_OP_OPTIONAL diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 0205e2944067..2748c69609e3 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1514,6 +1514,7 @@ struct kvm_x86_ops { unsigned long (*vcpu_get_apicv_inhibit_reasons)(struct kvm_vcpu *vcpu); void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu); + void (*rmp_page_level_adjust)(struct kvm *kvm, kvm_pfn_t pfn, int *level); }; struct kvm_x86_nested_ops { diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index c623019929a7..997318ecebd1 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -43,6 +43,7 @@ #include <linux/hash.h> #include <linux/kern_levels.h> #include <linux/kthread.h> +#include <linux/sev.h> #include <asm/page.h> #include <asm/memtype.h> @@ -2824,6 +2825,10 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, if (unlikely(!pte)) return PG_LEVEL_4K; + /* Adjust the page level based on the SEV-SNP RMP page level. */ + if (kvm_x86_ops.rmp_page_level_adjust) + static_call(kvm_x86_rmp_page_level_adjust)(kvm, pfn, &level); + return level; } diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index a5b90469683f..91d3d24e60d2 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3597,3 +3597,49 @@ struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu) return pfn_to_page(pfn); } + +static bool is_pfn_range_shared(kvm_pfn_t start, kvm_pfn_t end) +{ + int level; + + while (end > start) { + if (snp_lookup_rmpentry(start, &level) != 0) + return false; + start++; + } + + return true; +} + +void sev_rmp_page_level_adjust(struct kvm *kvm, kvm_pfn_t pfn, int *level) +{ + int rmp_level, assigned; + + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) + return; + + assigned = snp_lookup_rmpentry(pfn, &rmp_level); + if (unlikely(assigned < 0)) + return; + + if (!assigned) { + /* + * If all the pages are shared then no need to keep the RMP + * and NPT in sync. + */ + pfn = pfn & ~(PTRS_PER_PMD - 1); + if (is_pfn_range_shared(pfn, pfn + PTRS_PER_PMD)) + return; + } + + /* + * The hardware installs 2MB TLB entries to access to 1GB pages, + * therefore allow NPT to use 1GB pages when pfn was added as 2MB + * in the RMP table. + */ + if (rmp_level == PG_LEVEL_2M && (*level == PG_LEVEL_1G)) + return; + + /* Adjust the level to keep the NPT and RMP in sync */ + *level = min_t(size_t, *level, rmp_level); +} diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index b4bd64f94d3a..18e2cd4d9559 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4734,6 +4734,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .vcpu_get_apicv_inhibit_reasons = avic_vcpu_get_apicv_inhibit_reasons, .alloc_apic_backing_page = svm_alloc_apic_backing_page, + .rmp_page_level_adjust = sev_rmp_page_level_adjust, }; /* diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 71c011af098e..7782312a1cda 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -673,6 +673,7 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector); void sev_es_prepare_switch_to_guest(struct sev_es_save_area *hostsa); void sev_es_unmap_ghcb(struct vcpu_svm *svm); struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu); +void sev_rmp_page_level_adjust(struct kvm *kvm, kvm_pfn_t pfn, int *level); /* vmenter.S */