From 6f550484a15ea1b468665cdf59f020bf08ccb292 Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Thu, 18 Feb 2010 12:15:00 +0200 Subject: [PATCH] KVM: Fix load_guest_segment_descriptor() to inject page fault This patch injects page fault when reading descriptor in load_guest_segment_descriptor() fails with FAULT. Effects of this injection: This function is used by kvm_load_segment_descriptor() which is necessary for the following instructions: - mov seg,r/m16 - jmp far - pop ?s This patch makes it possible to emulate the page faults generated by these instructions. But be sure that unless we change the kvm_load_segment_descriptor()'s ret value propagation this patch has no effect. Signed-off-by: Takuya Yoshikawa Signed-off-by: Gleb Natapov Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f6ae4875d9d0..203ee7d0ed58 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4713,6 +4713,9 @@ static int load_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, { struct descriptor_table dtable; u16 index = selector >> 3; + int ret; + u32 err; + gva_t addr; get_segment_descriptor_dtable(vcpu, selector, &dtable); @@ -4720,9 +4723,13 @@ static int load_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, kvm_queue_exception_e(vcpu, GP_VECTOR, selector & 0xfffc); return X86EMUL_PROPAGATE_FAULT; } - return kvm_read_guest_virt_system(dtable.base + index*8, - seg_desc, sizeof(*seg_desc), - vcpu, NULL); + addr = dtable.base + index * 8; + ret = kvm_read_guest_virt_system(addr, seg_desc, sizeof(*seg_desc), + vcpu, &err); + if (ret == X86EMUL_PROPAGATE_FAULT) + kvm_inject_page_fault(vcpu, addr, err); + + return ret; } /* allowed just for 8 bytes segments */ -- 2.39.5