From: Joerg Roedel Date: Wed, 18 Jul 2007 16:51:36 +0000 (+0300) Subject: [PATCH] KVM: SVM: Reliably detect if SVM was disabled by BIOS X-Git-Tag: v2.6.20.17~45 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d4d4eb0442422123ac0fb4a560af2ad481817397;p=thirdparty%2Fkernel%2Fstable.git [PATCH] KVM: SVM: Reliably detect if SVM was disabled by BIOS This patch adds an implementation to the svm is_disabled function to detect reliably if the BIOS disabled the SVM feature in the CPU. This fixes the issues with kernel panics when loading the kvm-amd module on machines where SVM is available but disabled. Signed-off-by: Joerg Roedel Signed-off-by: Avi Kivity Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index c79df79307ed0..1e90401b56686 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -1655,6 +1655,12 @@ static void svm_inject_page_fault(struct kvm_vcpu *vcpu, static int is_disabled(void) { + u64 vm_cr; + + rdmsrl(MSR_VM_CR, vm_cr); + if (vm_cr & (1 << SVM_VM_CR_SVM_DISABLE)) + return 1; + return 0; } diff --git a/drivers/kvm/svm.h b/drivers/kvm/svm.h index df731c3fb5888..e8f0349556461 100644 --- a/drivers/kvm/svm.h +++ b/drivers/kvm/svm.h @@ -172,8 +172,11 @@ struct __attribute__ ((__packed__)) vmcb { #define SVM_CPUID_FUNC 0x8000000a #define MSR_EFER_SVME_MASK (1ULL << 12) +#define MSR_VM_CR 0xc0010114 #define MSR_VM_HSAVE_PA 0xc0010117ULL +#define SVM_VM_CR_SVM_DISABLE 4 + #define SVM_SELECTOR_S_SHIFT 4 #define SVM_SELECTOR_DPL_SHIFT 5 #define SVM_SELECTOR_P_SHIFT 7