KVM: nVMX: Use a gfn_to_hva_cache for vmptrld

And thus another call to kvm_vcpu_map() can die.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211115165030.7422-7-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4fb904ff7f125ca6e15953f7c41356a5c9013881..1e2f669515665b233e591343458c5ccce54ee32c 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5286,10 +5286,11 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
                return 1;
 
        if (vmx->nested.current_vmptr != vmptr) {
-               struct kvm_host_map map;
-               struct vmcs12 *new_vmcs12;
+               struct gfn_to_hva_cache *ghc = &vmx->nested.vmcs12_cache;
+               struct vmcs_hdr hdr;
 
-               if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmptr), &map)) {
+               if (ghc->gpa != vmptr &&
+                   kvm_gfn_to_hva_cache_init(vcpu->kvm, ghc, vmptr, VMCS12_SIZE)) {
                        /*
                         * Reads from an unbacked page return all 1s,
                         * which means that the 32 bits located at the
@@ -5300,12 +5301,16 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
                                VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
                }
 
-               new_vmcs12 = map.hva;
+               if (kvm_read_guest_offset_cached(vcpu->kvm, ghc, &hdr,
+                                                offsetof(struct vmcs12, hdr),
+                                                sizeof(hdr))) {
+                       return nested_vmx_fail(vcpu,
+                               VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
+               }
 
-               if (new_vmcs12->hdr.revision_id != VMCS12_REVISION ||
-                   (new_vmcs12->hdr.shadow_vmcs &&
+               if (hdr.revision_id != VMCS12_REVISION ||
+                   (hdr.shadow_vmcs &&
                     !nested_cpu_has_vmx_shadow_vmcs(vcpu))) {
-                       kvm_vcpu_unmap(vcpu, &map, false);
                        return nested_vmx_fail(vcpu,
                                VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
                }
@@ -5316,8 +5321,11 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
                 * Load VMCS12 from guest memory since it is not already
                 * cached.
                 */
-               memcpy(vmx->nested.cached_vmcs12, new_vmcs12, VMCS12_SIZE);
-               kvm_vcpu_unmap(vcpu, &map, false);
+               if (kvm_read_guest_cached(vcpu->kvm, ghc, vmx->nested.cached_vmcs12,
+                                         VMCS12_SIZE)) {
+                       return nested_vmx_fail(vcpu,
+                               VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
+               }
 
                set_current_vmptr(vmx, vmptr);
        }

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index cdadbd5dc0ca0cb2899f29fd92e8dbb8f977206e..4df2ac24ffc13009db0f43486450594a4d35432b 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -146,6 +146,11 @@ struct nested_vmx {
         */
        struct gfn_to_hva_cache shadow_vmcs12_cache;
 
+       /*
+        * GPA to HVA cache for VMCS12
+        */
+       struct gfn_to_hva_cache vmcs12_cache;
+
        /*
         * Indicates if the shadow vmcs or enlightened vmcs must be updated
         * with the data held by struct vmcs12.