[07/11] KVM: nVMX: Use a gfn_to_hva_cache for vmptrld

Commit Message

David Woodhouse Nov. 15, 2021, 4:50 p.m. UTC

From: David Woodhouse <[e-mail]>

And thus another call to kvm_vcpu_map() can die.

Signed-off-by: David Woodhouse <[e-mail]>
---
 arch/x86/kvm/vmx/nested.c | 26 +++++++++++++++++---------
 arch/x86/kvm/vmx/vmx.h    |  5 +++++
 2 files changed, 22 insertions(+), 9 deletions(-)

Patch

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 070bf9558b2a..280f34ea02c3 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5274,10 +5274,11 @@  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
@@ -5288,12 +5289,16 @@  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);
 		}
@@ -5304,8 +5309,11 @@  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 cdadbd5dc0ca..4df2ac24ffc1 100644
--- 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.