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| author | Sean Christopherson <seanjc@google.com> | 2022-06-07 21:35:50 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-07-28 13:22:25 -0400 |
| commit | c33f6f2228fe8517e38941a508e9f905f99ecba9 (patch) | |
| tree | 0cb78fa6d7c2e2b303b937be5bf2a5b096ebf3df /arch/x86/kvm/svm/nested.c | |
| parent | cfe12e64b0657142824819d939fcfe62f14104a1 (diff) | |
| download | linux-c33f6f2228fe8517e38941a508e9f905f99ecba9.tar.bz2 | |
KVM: x86: Split kvm_is_valid_cr4() and export only the non-vendor bits
Split the common x86 parts of kvm_is_valid_cr4(), i.e. the reserved bits
checks, into a separate helper, __kvm_is_valid_cr4(), and export only the
inner helper to vendor code in order to prevent nested VMX from calling
back into vmx_is_valid_cr4() via kvm_is_valid_cr4().
On SVM, this is a nop as SVM doesn't place any additional restrictions on
CR4.
On VMX, this is also currently a nop, but only because nested VMX is
missing checks on reserved CR4 bits for nested VM-Enter. That bug will
be fixed in a future patch, and could simply use kvm_is_valid_cr4() as-is,
but nVMX has _another_ bug where VMXON emulation doesn't enforce VMX's
restrictions on CR0/CR4. The cleanest and most intuitive way to fix the
VMXON bug is to use nested_host_cr{0,4}_valid(). If the CR4 variant
routes through kvm_is_valid_cr4(), using nested_host_cr4_valid() won't do
the right thing for the VMXON case as vmx_is_valid_cr4() enforces VMX's
restrictions if and only if the vCPU is post-VMXON.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220607213604.3346000-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm/nested.c')
| -rw-r--r-- | arch/x86/kvm/svm/nested.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 23252ab82194..76dcc8a3e849 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -325,7 +325,8 @@ static bool __nested_vmcb_check_save(struct kvm_vcpu *vcpu, return false; } - if (CC(!kvm_is_valid_cr4(vcpu, save->cr4))) + /* Note, SVM doesn't have any additional restrictions on CR4. */ + if (CC(!__kvm_is_valid_cr4(vcpu, save->cr4))) return false; if (CC(!kvm_valid_efer(vcpu, save->efer))) |