| Message ID | 20230220183847.59159-51-michael.roth@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On Mon, 20 Feb 2023 12:38:41 -0600 Michael Roth <michael.roth@amd.com> wrote: > Implement a platform hook to do the work of restoring the direct map > entries and cleaning up RMP table entries for restricted memory that is > being freed back to the host. > > Signed-off-by: Michael Roth <michael.roth@amd.com> > --- > arch/x86/kvm/svm/sev.c | 62 ++++++++++++++++++++++++++++++++++++++++++ > arch/x86/kvm/svm/svm.c | 1 + > arch/x86/kvm/svm/svm.h | 1 + > 3 files changed, 64 insertions(+) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 7a74a92cb39a..bedec90d034f 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -4509,3 +4509,65 @@ bool sev_fault_is_private(struct kvm *kvm, gpa_t gpa, u64 error_code, bool *priv > > return true; > } > + > +void sev_invalidate_private_range(struct kvm_memory_slot *slot, gfn_t start, gfn_t end) > +{ > + gfn_t gfn = start; > + > + if (!sev_snp_guest(slot->kvm)) > + return; > + > + if (!kvm_slot_can_be_private(slot)) { > + pr_warn_ratelimited("SEV: Memslot for GFN: 0x%llx is not private.\n", > + gfn); > + return; > + } > + This is a generic check for both SNP and TDX, it should be moved to kvm_restrictedmem_invalidate_begin(). > + while (gfn <= end) { > + gpa_t gpa = gfn_to_gpa(gfn); > + int level = PG_LEVEL_4K; > + int order, rc; > + kvm_pfn_t pfn; > + > + rc = kvm_restrictedmem_get_pfn(slot, gfn, &pfn, &order); > + if (rc) { > + pr_warn_ratelimited("SEV: Failed to retrieve restricted PFN for GFN 0x%llx, rc: %d\n", > + gfn, rc); > + gfn++; > + continue; > + } > + > + if (order) { > + int rmp_level; > + > + if (IS_ALIGNED(gpa, page_level_size(PG_LEVEL_2M)) && > + gpa + page_level_size(PG_LEVEL_2M) <= gfn_to_gpa(end)) > + level = PG_LEVEL_2M; > + else > + pr_debug("%s: GPA 0x%llx is not aligned to 2M, skipping 2M directmap restoration\n", > + __func__, gpa); > + > + /* > + * TODO: It may still be possible to restore 2M mapping here, > + * but keep it simple for now. > + */ > + if (level == PG_LEVEL_2M && > + (!snp_lookup_rmpentry(pfn, &rmp_level) || rmp_level == PG_LEVEL_4K)) { > + pr_debug("%s: PFN 0x%llx is not mapped as 2M private range, skipping 2M directmap restoration\n", > + __func__, pfn); > + level = PG_LEVEL_4K; > + } > + } > + > + pr_debug("%s: GPA %llx PFN %llx order %d level %d\n", > + __func__, gpa, pfn, order, level); > + rc = snp_make_page_shared(slot->kvm, gpa, pfn, level); > + if (rc) > + pr_err("SEV: Failed to restore page to shared, GPA: 0x%llx PFN: 0x%llx order: %d rc: %d\n", > + gpa, pfn, order, rc); > + > + gfn += page_level_size(level) >> PAGE_SHIFT; > + put_page(pfn_to_page(pfn)); > + cond_resched(); > + } > +} > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 18e4a6c17d11..3fe5f13b5f3a 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -4862,6 +4862,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { > .adjust_mapping_level = sev_adjust_mapping_level, > .update_mem_attr = sev_update_mem_attr, > .fault_is_private = sev_fault_is_private, > + .invalidate_restricted_mem = sev_invalidate_private_range, > }; > > /* > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 97038afa8020..857b674e68f0 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -727,6 +727,7 @@ void handle_rmp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code); > void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu); > int sev_update_mem_attr(struct kvm_memory_slot *slot, unsigned int attr, > gfn_t start, gfn_t end); > +void sev_invalidate_private_range(struct kvm_memory_slot *slot, gfn_t start, gfn_t end); > > bool sev_fault_is_private(struct kvm *kvm, gpa_t gpa, u64 error_code, bool *private_fault); >
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 7a74a92cb39a..bedec90d034f 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -4509,3 +4509,65 @@ bool sev_fault_is_private(struct kvm *kvm, gpa_t gpa, u64 error_code, bool *priv return true; } + +void sev_invalidate_private_range(struct kvm_memory_slot *slot, gfn_t start, gfn_t end) +{ + gfn_t gfn = start; + + if (!sev_snp_guest(slot->kvm)) + return; + + if (!kvm_slot_can_be_private(slot)) { + pr_warn_ratelimited("SEV: Memslot for GFN: 0x%llx is not private.\n", + gfn); + return; + } + + while (gfn <= end) { + gpa_t gpa = gfn_to_gpa(gfn); + int level = PG_LEVEL_4K; + int order, rc; + kvm_pfn_t pfn; + + rc = kvm_restrictedmem_get_pfn(slot, gfn, &pfn, &order); + if (rc) { + pr_warn_ratelimited("SEV: Failed to retrieve restricted PFN for GFN 0x%llx, rc: %d\n", + gfn, rc); + gfn++; + continue; + } + + if (order) { + int rmp_level; + + if (IS_ALIGNED(gpa, page_level_size(PG_LEVEL_2M)) && + gpa + page_level_size(PG_LEVEL_2M) <= gfn_to_gpa(end)) + level = PG_LEVEL_2M; + else + pr_debug("%s: GPA 0x%llx is not aligned to 2M, skipping 2M directmap restoration\n", + __func__, gpa); + + /* + * TODO: It may still be possible to restore 2M mapping here, + * but keep it simple for now. + */ + if (level == PG_LEVEL_2M && + (!snp_lookup_rmpentry(pfn, &rmp_level) || rmp_level == PG_LEVEL_4K)) { + pr_debug("%s: PFN 0x%llx is not mapped as 2M private range, skipping 2M directmap restoration\n", + __func__, pfn); + level = PG_LEVEL_4K; + } + } + + pr_debug("%s: GPA %llx PFN %llx order %d level %d\n", + __func__, gpa, pfn, order, level); + rc = snp_make_page_shared(slot->kvm, gpa, pfn, level); + if (rc) + pr_err("SEV: Failed to restore page to shared, GPA: 0x%llx PFN: 0x%llx order: %d rc: %d\n", + gpa, pfn, order, rc); + + gfn += page_level_size(level) >> PAGE_SHIFT; + put_page(pfn_to_page(pfn)); + cond_resched(); + } +} diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 18e4a6c17d11..3fe5f13b5f3a 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4862,6 +4862,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .adjust_mapping_level = sev_adjust_mapping_level, .update_mem_attr = sev_update_mem_attr, .fault_is_private = sev_fault_is_private, + .invalidate_restricted_mem = sev_invalidate_private_range, }; /* diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 97038afa8020..857b674e68f0 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -727,6 +727,7 @@ void handle_rmp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code); void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu); int sev_update_mem_attr(struct kvm_memory_slot *slot, unsigned int attr, gfn_t start, gfn_t end); +void sev_invalidate_private_range(struct kvm_memory_slot *slot, gfn_t start, gfn_t end); bool sev_fault_is_private(struct kvm *kvm, gpa_t gpa, u64 error_code, bool *private_fault);
Implement a platform hook to do the work of restoring the direct map entries and cleaning up RMP table entries for restricted memory that is being freed back to the host. Signed-off-by: Michael Roth <michael.roth@amd.com> --- arch/x86/kvm/svm/sev.c | 62 ++++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/svm/svm.c | 1 + arch/x86/kvm/svm/svm.h | 1 + 3 files changed, 64 insertions(+)