diff options
| author | Xiaoyao Li <xiaoyao.li@intel.com> | 2020-04-10 13:54:02 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-04-11 16:42:41 +0200 |
| commit | e6f8b6c12f03818baacc5f504fe83fa5e20771d6 (patch) | |
| tree | 45e390cc34bd88cc38cc26acc093ca74b59141d6 /arch | |
| parent | KVM: x86: Emulate split-lock access as a write in emulator (diff) | |
| download | linux-e6f8b6c12f03818baacc5f504fe83fa5e20771d6.tar.xz linux-e6f8b6c12f03818baacc5f504fe83fa5e20771d6.zip | |
KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest
Two types of #AC can be generated in Intel CPUs:
1. legacy alignment check #AC
2. split lock #AC
Reflect #AC back into the guest if the guest has legacy alignment checks
enabled or if split lock detection is disabled.
If the #AC is not a legacy one and split lock detection is enabled, then
invoke handle_guest_split_lock() which will either warn and disable split
lock detection for this task or force SIGBUS on it.
[ tglx: Switch it to handle_guest_split_lock() and rename the misnamed
helper function. ]
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20200410115517.176308876@linutronix.de
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 37 |
1 files changed, 34 insertions, 3 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 8959514eaf0f..83050977490c 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4588,6 +4588,26 @@ static int handle_machine_check(struct kvm_vcpu *vcpu) return 1; } +/* + * If the host has split lock detection disabled, then #AC is + * unconditionally injected into the guest, which is the pre split lock + * detection behaviour. + * + * If the host has split lock detection enabled then #AC is + * only injected into the guest when: + * - Guest CPL == 3 (user mode) + * - Guest has #AC detection enabled in CR0 + * - Guest EFLAGS has AC bit set + */ +static inline bool guest_inject_ac(struct kvm_vcpu *vcpu) +{ + if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) + return true; + + return vmx_get_cpl(vcpu) == 3 && kvm_read_cr0_bits(vcpu, X86_CR0_AM) && + (kvm_get_rflags(vcpu) & X86_EFLAGS_AC); +} + static int handle_exception_nmi(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); @@ -4653,9 +4673,6 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) return handle_rmode_exception(vcpu, ex_no, error_code); switch (ex_no) { - case AC_VECTOR: - kvm_queue_exception_e(vcpu, AC_VECTOR, error_code); - return 1; case DB_VECTOR: dr6 = vmcs_readl(EXIT_QUALIFICATION); if (!(vcpu->guest_debug & @@ -4684,6 +4701,20 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip; kvm_run->debug.arch.exception = ex_no; break; + case AC_VECTOR: + if (guest_inject_ac(vcpu)) { + kvm_queue_exception_e(vcpu, AC_VECTOR, error_code); + return 1; + } + + /* + * Handle split lock. Depending on detection mode this will + * either warn and disable split lock detection for this + * task or force SIGBUS on it. + */ + if (handle_guest_split_lock(kvm_rip_read(vcpu))) + return 1; + fallthrough; default: kvm_run->exit_reason = KVM_EXIT_EXCEPTION; kvm_run->ex.exception = ex_no; |