diff options
| author | David Matlack <dmatlack@google.com> | 2016-11-30 03:14:09 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-12-08 15:31:08 +0100 |
| commit | 8322ebbb24088c22049ef53cd066c6c220640edb (patch) | |
| tree | d91152a0df6fc1700e5f6c296f0f553b6572e439 /arch/x86/kvm | |
| parent | KVM: nVMX: fix checks on CR{0,4} during virtual VMX operation (diff) | |
| download | linux-8322ebbb24088c22049ef53cd066c6c220640edb.tar.xz linux-8322ebbb24088c22049ef53cd066c6c220640edb.zip | |
KVM: nVMX: generate MSR_IA32_CR{0,4}_FIXED1 from guest CPUID
MSR_IA32_CR{0,4}_FIXED1 define which bits in CR0 and CR4 are allowed to
be 1 during VMX operation. Since the set of allowed-1 bits is the same
in and out of VMX operation, we can generate these MSRs entirely from
the guest's CPUID. This lets userspace avoiding having to save/restore
these MSRs.
This patch also initializes MSR_IA32_CR{0,4}_FIXED1 from the CPU's MSRs
by default. This is a saner than the current default of -1ull, which
includes bits that the host CPU does not support.
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 55 |
1 files changed, 52 insertions, 3 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 2b8d4f5ac246..fa29585c63ff 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2877,16 +2877,18 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx) vmx->nested.nested_vmx_basic |= VMX_BASIC_INOUT; /* - * These MSRs specify bits which the guest must keep fixed (on or off) + * These MSRs specify bits which the guest must keep fixed on * while L1 is in VMXON mode (in L1's root mode, or running an L2). * We picked the standard core2 setting. */ #define VMXON_CR0_ALWAYSON (X86_CR0_PE | X86_CR0_PG | X86_CR0_NE) #define VMXON_CR4_ALWAYSON X86_CR4_VMXE vmx->nested.nested_vmx_cr0_fixed0 = VMXON_CR0_ALWAYSON; - vmx->nested.nested_vmx_cr0_fixed1 = -1ULL; vmx->nested.nested_vmx_cr4_fixed0 = VMXON_CR4_ALWAYSON; - vmx->nested.nested_vmx_cr4_fixed1 = -1ULL; + + /* These MSRs specify bits which the guest must keep fixed off. */ + rdmsrl(MSR_IA32_VMX_CR0_FIXED1, vmx->nested.nested_vmx_cr0_fixed1); + rdmsrl(MSR_IA32_VMX_CR4_FIXED1, vmx->nested.nested_vmx_cr4_fixed1); /* highest index: VMX_PREEMPTION_TIMER_VALUE */ vmx->nested.nested_vmx_vmcs_enum = 0x2e; @@ -9424,6 +9426,50 @@ static void vmcs_set_secondary_exec_control(u32 new_ctl) (new_ctl & ~mask) | (cur_ctl & mask)); } +/* + * Generate MSR_IA32_VMX_CR{0,4}_FIXED1 according to CPUID. Only set bits + * (indicating "allowed-1") if they are supported in the guest's CPUID. + */ +static void nested_vmx_cr_fixed1_bits_update(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + struct kvm_cpuid_entry2 *entry; + + vmx->nested.nested_vmx_cr0_fixed1 = 0xffffffff; + vmx->nested.nested_vmx_cr4_fixed1 = X86_CR4_PCE; + +#define cr4_fixed1_update(_cr4_mask, _reg, _cpuid_mask) do { \ + if (entry && (entry->_reg & (_cpuid_mask))) \ + vmx->nested.nested_vmx_cr4_fixed1 |= (_cr4_mask); \ +} while (0) + + entry = kvm_find_cpuid_entry(vcpu, 0x1, 0); + cr4_fixed1_update(X86_CR4_VME, edx, bit(X86_FEATURE_VME)); + cr4_fixed1_update(X86_CR4_PVI, edx, bit(X86_FEATURE_VME)); + cr4_fixed1_update(X86_CR4_TSD, edx, bit(X86_FEATURE_TSC)); + cr4_fixed1_update(X86_CR4_DE, edx, bit(X86_FEATURE_DE)); + cr4_fixed1_update(X86_CR4_PSE, edx, bit(X86_FEATURE_PSE)); + cr4_fixed1_update(X86_CR4_PAE, edx, bit(X86_FEATURE_PAE)); + cr4_fixed1_update(X86_CR4_MCE, edx, bit(X86_FEATURE_MCE)); + cr4_fixed1_update(X86_CR4_PGE, edx, bit(X86_FEATURE_PGE)); + cr4_fixed1_update(X86_CR4_OSFXSR, edx, bit(X86_FEATURE_FXSR)); + cr4_fixed1_update(X86_CR4_OSXMMEXCPT, edx, bit(X86_FEATURE_XMM)); + cr4_fixed1_update(X86_CR4_VMXE, ecx, bit(X86_FEATURE_VMX)); + cr4_fixed1_update(X86_CR4_SMXE, ecx, bit(X86_FEATURE_SMX)); + cr4_fixed1_update(X86_CR4_PCIDE, ecx, bit(X86_FEATURE_PCID)); + cr4_fixed1_update(X86_CR4_OSXSAVE, ecx, bit(X86_FEATURE_XSAVE)); + + entry = kvm_find_cpuid_entry(vcpu, 0x7, 0); + cr4_fixed1_update(X86_CR4_FSGSBASE, ebx, bit(X86_FEATURE_FSGSBASE)); + cr4_fixed1_update(X86_CR4_SMEP, ebx, bit(X86_FEATURE_SMEP)); + cr4_fixed1_update(X86_CR4_SMAP, ebx, bit(X86_FEATURE_SMAP)); + cr4_fixed1_update(X86_CR4_PKE, ecx, bit(X86_FEATURE_PKU)); + /* TODO: Use X86_CR4_UMIP and X86_FEATURE_UMIP macros */ + cr4_fixed1_update(bit(11), ecx, bit(2)); + +#undef cr4_fixed1_update +} + static void vmx_cpuid_update(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best; @@ -9465,6 +9511,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu) else to_vmx(vcpu)->msr_ia32_feature_control_valid_bits &= ~FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX; + + if (nested_vmx_allowed(vcpu)) + nested_vmx_cr_fixed1_bits_update(vcpu); } static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry) |