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authorSean Christopherson <seanjc@google.com>2022-06-07 21:36:00 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2022-07-28 13:25:01 -0400
commita910b5ab6b250a88fff1866bf708642d83317466 (patch)
tree1efb97995e4c22d2201fee0f2bd66c7bf606c223 /arch/x86/kvm
parentRevert "KVM: nVMX: Expose load IA32_PERF_GLOBAL_CTRL VM-{Entry,Exit} control" (diff)
downloadlinux-dev-a910b5ab6b250a88fff1866bf708642d83317466.tar.xz
linux-dev-a910b5ab6b250a88fff1866bf708642d83317466.zip
KVM: nVMX: Set UMIP bit CR4_FIXED1 MSR when emulating UMIP
Make UMIP an "allowed-1" bit CR4_FIXED1 MSR when KVM is emulating UMIP. KVM emulates UMIP for both L1 and L2, and so should enumerate that L2 is allowed to have CR4.UMIP=1. Not setting the bit doesn't immediately break nVMX, as KVM does set/clear the bit in CR4_FIXED1 in response to a guest CPUID update, i.e. KVM will correctly (dis)allow nested VM-Entry based on whether or not UMIP is exposed to L1. That said, KVM should enumerate the bit as being allowed from time zero, e.g. userspace will see the wrong value if the MSR is read before CPUID is written. Fixes: 0367f205a3b7 ("KVM: vmx: add support for emulating UMIP") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220607213604.3346000-12-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/vmx/nested.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index ebeeddb6aeb1..ed247a121325 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -6757,6 +6757,9 @@ void nested_vmx_setup_ctls_msrs(struct nested_vmx_msrs *msrs, u32 ept_caps)
rdmsrl(MSR_IA32_VMX_CR0_FIXED1, msrs->cr0_fixed1);
rdmsrl(MSR_IA32_VMX_CR4_FIXED1, msrs->cr4_fixed1);
+ if (vmx_umip_emulated())
+ msrs->cr4_fixed1 |= X86_CR4_UMIP;
+
msrs->vmcs_enum = nested_vmx_calc_vmcs_enum_msr();
}