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 <yoshikawa.takuya@xxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b2f91b9..38cb488 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4655,6 +4655,7 @@ static int load_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
{
struct descriptor_table dtable;
u16 index = selector >> 3;
+ int ret;
get_segment_descriptor_dtable(vcpu, selector, &dtable);
@@ -4662,7 +4663,11 @@ 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(dtable.base + index*8, seg_desc, sizeof(*seg_desc), vcpu);
+ ret = kvm_read_guest_virt(dtable.base + index*8, seg_desc, sizeof(*seg_desc), vcpu);
+ if (ret == X86EMUL_PROPAGATE_FAULT)
+ kvm_inject_page_fault(vcpu, dtable.base + index*8, 0);
+
+ return ret;
}
/* allowed just for 8 bytes segments */
--
1.6.3.3
--
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