@@ -135,6 +135,7 @@ 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_OPTIONAL_RET0(gmem_prepare)
+KVM_X86_OP_OPTIONAL_RET0(gmem_max_level)
KVM_X86_OP_OPTIONAL(gmem_invalidate)
KVM_X86_OP_OPTIONAL(alloc_apic_backing_page)
@@ -1764,6 +1764,7 @@ struct kvm_x86_ops {
int (*gmem_prepare)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order);
void (*gmem_invalidate)(kvm_pfn_t start, kvm_pfn_t end);
+ int (*gmem_max_level)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, u8 *max_level);
void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu);
};
@@ -4304,6 +4304,7 @@ static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu,
struct kvm_page_fault *fault)
{
int max_order, r;
+ u8 max_level;
if (!kvm_slot_can_be_private(fault->slot)) {
kvm_mmu_prepare_memory_fault_exit(vcpu, fault);
@@ -4317,8 +4318,15 @@ static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu,
return r;
}
- fault->max_level = min(kvm_max_level_for_order(max_order),
- fault->max_level);
+ max_level = kvm_max_level_for_order(max_order);
+ r = static_call(kvm_x86_gmem_max_level)(vcpu->kvm, fault->pfn,
+ fault->gfn, &max_level);
+ if (r) {
+ kvm_release_pfn_clean(fault->pfn);
+ return r;
+ }
+
+ fault->max_level = min(max_level, fault->max_level);
fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY);
return RET_PF_CONTINUE;
@@ -4293,3 +4293,30 @@ void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)
pfn += use_2m_update ? PTRS_PER_PMD : 1;
}
}
+
+int sev_gmem_max_level(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, u8 *max_level)
+{
+ int level, rc;
+ bool assigned;
+
+ if (!sev_snp_guest(kvm))
+ return 0;
+
+ rc = snp_lookup_rmpentry(pfn, &assigned, &level);
+ if (rc) {
+ pr_err_ratelimited("SEV: RMP entry not found: GFN %llx PFN %llx level %d error %d\n",
+ gfn, pfn, level, rc);
+ return -ENOENT;
+ }
+
+ if (!assigned) {
+ pr_err_ratelimited("SEV: RMP entry is not assigned: GFN %llx PFN %llx level %d\n",
+ gfn, pfn, level);
+ return -EINVAL;
+ }
+
+ if (level < *max_level)
+ *max_level = level;
+
+ return 0;
+}
@@ -5043,6 +5043,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.alloc_apic_backing_page = svm_alloc_apic_backing_page,
.gmem_prepare = sev_gmem_prepare,
+ .gmem_max_level = sev_gmem_max_level,
.gmem_invalidate = sev_gmem_invalidate,
};
In the case of SEV-SNP, whether or not a 2MB page can be mapped via a 2MB mapping in the guest's nested page table depends on whether or not any subpages within the range have already been initialized as private in the RMP table. The existing mixed-attribute tracking in KVM is insufficient here, for instance: - gmem allocates 2MB page - guest issues PVALIDATE on 2MB page - guest later converts a subpage to shared - SNP host code issues PSMASH to split 2MB RMP mapping to 4K - KVM MMU splits NPT mapping to 4K At this point there are no mixed attributes, and KVM would normally allow for 2MB NPT mappings again, but this is actually not allowed because the RMP table mappings are 4K and cannot be promoted on the hypervisor side, so the NPT mappings must still be limited to 4K to match this. Add a hook to determine the max NPT mapping size in situations like this. Signed-off-by: Michael Roth <michael.roth@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 | 12 ++++++++++-- arch/x86/kvm/svm/sev.c | 27 +++++++++++++++++++++++++++ arch/x86/kvm/svm/svm.c | 1 + 5 files changed, 40 insertions(+), 2 deletions(-)