kvm: x86: Toggling CR4.PKE does not load PDPTEs in PAE mode

jsmattsonjr · bonzini · commit cb957adb4ea4 · 2020-08-17T15:24:08.000-04:00
See the SDM, volume 3, section 4.4.1: If PAE paging would be in use following an execution of MOV to CR0 or MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then the PDPTEs are loaded from the address in CR3. Fixes: b9baba8 ("KVM, pkeys: expose CPUID/CR4 to guest") Cc: Huaitong Han <huaitong.han@intel.com> Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Peter Shier <pshier@google.com> Reviewed-by: Oliver Upton <oupton@google.com> Message-Id: <20200817181655.3716509-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
@@ -975,7 +975,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 {
 	unsigned long old_cr4 = kvm_read_cr4(vcpu);
 	unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE |
-				   X86_CR4_SMEP | X86_CR4_PKE;
+				   X86_CR4_SMEP;
 
 	if (kvm_valid_cr4(vcpu, cr4))
 		return 1;

Original file line number	Diff line number	Diff line change
`@@ -975,7 +975,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)`
`975`	`975`	`{`
`976`	`976`	`unsigned long old_cr4 = kvm_read_cr4(vcpu);`
`977`	`977`	`unsigned long pdptr_bits = X86_CR4_PGE \| X86_CR4_PSE \| X86_CR4_PAE \|`
`978`		`- X86_CR4_SMEP \| X86_CR4_PKE;`
	`978`	`+ X86_CR4_SMEP;`
`979`	`979`
`980`	`980`	`if (kvm_valid_cr4(vcpu, cr4))`
`981`	`981`	`return 1;`