In the segment descriptor _cache_ the accessed bit is always set (although it can be cleared in the descriptor itself). Since Intel checks for this condition on a VMENTRY, set this bit in the AMD path to enable cross vendor migration.
Signed-off-by: Andre Przywara <[email protected]> --- arch/x86/kvm/svm.c | 22 +++++++++++++++++++--- 1 files changed, 19 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 32dafb7..ffaba66 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -793,20 +793,36 @@ static void svm_get_segment(struct kvm_vcpu *vcpu, var->db = (s->attrib >> SVM_SELECTOR_DB_SHIFT) & 1; var->g = (s->attrib >> SVM_SELECTOR_G_SHIFT) & 1; + switch (seg) { + case VCPU_SREG_CS: /* * SVM always stores 0 for the 'G' bit in the CS selector in * the VMCB on a VMEXIT. This hurts cross-vendor migration: * Intel's VMENTRY has a check on the 'G' bit. */ - if (seg == VCPU_SREG_CS) var->g = s->limit > 0xfffff; - + break; + case VCPU_SREG_TR: /* * Work around a bug where the busy flag in the tr selector * isn't exposed */ - if (seg == VCPU_SREG_TR) var->type |= 0x2; + break; + case VCPU_SREG_DS: + case VCPU_SREG_ES: + case VCPU_SREG_FS: + case VCPU_SREG_GS: + /* + * The accessed bit must always be set in the segment + * descriptor cache, although it can be cleared in the + * descriptor, the cached bit always remains at 1. Since + * Intel has a check on this, set it here to support + * cross-vendor migration. + */ + if (!var->unusable) var->type |= 0x1; + break; + } var->unusable = !var->present; } -- 1.5.2.2 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
