This reverts commit 5045b468037dfe1c848827ce10e99d87f5669160. Although the
cs.dpl=cs.rpl check is mentioned in table 7-1 of the SDM as causing a #TSS
exception, it is not mentioned in table 6-6 that lists "invalid TSS conditions"
which cause #TSS exceptions. As it causes some tests, which pass on bare-metal,
to fail - it should be reverted.
Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 32 +++++++++++++++-----------------
1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 56657b0..b73c9e8 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1415,7 +1415,7 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
/* Does not support long mode */
static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
- u16 selector, int seg, u8 cpl, bool in_task_switch)
+ u16 selector, int seg, u8 cpl)
{
struct desc_struct seg_desc, old_desc;
u8 dpl, rpl;
@@ -1491,9 +1491,6 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
goto exception;
break;
case VCPU_SREG_CS:
- if (in_task_switch && rpl != dpl)
- goto exception;
-
if (!(seg_desc.type & 8))
goto exception;
@@ -1560,7 +1557,7 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
u16 selector, int seg)
{
u8 cpl = ctxt->ops->cpl(ctxt);
- return __load_segment_descriptor(ctxt, selector, seg, cpl, false);
+ return __load_segment_descriptor(ctxt, selector, seg, cpl);
}
static void write_register_operand(struct operand *op)
@@ -2460,19 +2457,19 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
* Now load segment descriptors. If fault happens at this stage
* it is handled in a context of new task
*/
- ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
@@ -2597,25 +2594,26 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
* Now load segment descriptors. If fault happenes at this stage
* it is handled in a context of new task
*/
- ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR,
+ cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl, true);
+ ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl);
if (ret != X86EMUL_CONTINUE)
return ret;
--
1.9.1
--
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