diff options
| author | Mathias Krause <minipli@grsecurity.net> | 2023-03-22 02:37:31 +0100 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-03-22 07:47:26 -0700 |
| commit | fb509f76acc8d42bed11bca308404f81c2be856a (patch) | |
| tree | b4d975c9aaeb6119487503174ba298ffc3090cd3 /arch/x86/kvm/kvm_cache_regs.h | |
| parent | 74cdc836919bf34684ef66f995273f35e2189daf (diff) | |
KVM: VMX: Make CR0.WP a guest owned bit
Guests like grsecurity that make heavy use of CR0.WP to implement kernel
level W^X will suffer from the implied VMEXITs.
With EPT there is no need to intercept a guest change of CR0.WP, so
simply make it a guest owned bit if we can do so.
This implies that a read of a guest's CR0.WP bit might need a VMREAD.
However, the only potentially affected user seems to be kvm_init_mmu()
which is a heavy operation to begin with. But also most callers already
cache the full value of CR0 anyway, so no additional VMREAD is needed.
The only exception is nested_vmx_load_cr3().
This change is VMX-specific, as SVM has no such fine grained control
register intercept control.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20230322013731.102955-7-minipli@grsecurity.net
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/kvm_cache_regs.h')
| -rw-r--r-- | arch/x86/kvm/kvm_cache_regs.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index 4c91f626c058..e50d353b5c1c 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -4,7 +4,7 @@ #include <linux/kvm_host.h> -#define KVM_POSSIBLE_CR0_GUEST_BITS X86_CR0_TS +#define KVM_POSSIBLE_CR0_GUEST_BITS (X86_CR0_TS | X86_CR0_WP) #define KVM_POSSIBLE_CR4_GUEST_BITS \ (X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR \ | X86_CR4_OSXMMEXCPT | X86_CR4_PGE | X86_CR4_TSD | X86_CR4_FSGSBASE) |