This means that the truncation behavior in linearize needs to grow an additional
slight piece of complexity: when fetching, truncation is dependent on the
execution mode, instead of the current address size.
Signed-off-by: Nelson Elhage <nelhage@xxxxxxxxxxx>
---
arch/x86/include/asm/kvm_emulate.h | 1 -
arch/x86/kvm/emulate.c | 23 ++++++++++++-----------
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 0818448..9b760c8 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -265,7 +265,6 @@ struct x86_emulate_ctxt {
unsigned long eip; /* eip before instruction emulation */
/* Emulated execution mode, represented by an X86EMUL_MODE value. */
int mode;
- u32 cs_base;
/* interruptibility state, as a result of execution of STI or MOV SS */
int interruptibility;
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a5f63d4..d3d43a7 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -542,7 +542,7 @@ static int emulate_nm(struct x86_emulate_ctxt *ctxt)
static int linearize(struct x86_emulate_ctxt *ctxt,
struct segmented_address addr,
- unsigned size, bool write,
+ unsigned size, bool write, bool fetch,
ulong *linear)
{
struct decode_cache *c = &ctxt->decode;
@@ -602,7 +602,7 @@ static int linearize(struct x86_emulate_ctxt *ctxt,
}
break;
}
- if (c->ad_bytes != 8)
+ if (fetch ? ctxt->mode != X86EMUL_MODE_PROT64 : c->ad_bytes != 8)
la &= (u32)-1;
*linear = la;
return X86EMUL_CONTINUE;
@@ -621,7 +621,7 @@ static int segmented_read_std(struct x86_emulate_ctxt *ctxt,
int rc;
ulong linear;
- rc = linearize(ctxt, addr, size, false, &linear);
+ rc = linearize(ctxt, addr, size, false, false, &linear);
if (rc != X86EMUL_CONTINUE)
return rc;
return ctxt->ops->read_std(linear, data, size, ctxt->vcpu,
@@ -637,11 +637,13 @@ static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
int size, cur_size;
if (eip == fc->end) {
- unsigned long linear = eip + ctxt->cs_base;
- if (ctxt->mode != X86EMUL_MODE_PROT64)
- linear &= (u32)-1;
+ unsigned long linear;
+ struct segmented_address addr = {VCPU_SREG_CS, eip};
cur_size = fc->end - fc->start;
size = min(15UL - cur_size, PAGE_SIZE - offset_in_page(eip));
+ rc = linearize(ctxt, addr, size, false, true, &linear);
+ f (rc != X86EMUL_CONTINUE)
+ return rc;
rc = ops->fetch(linear, fc->data + cur_size,
size, ctxt->vcpu, &ctxt->exception);
if (rc != X86EMUL_CONTINUE)
@@ -1047,7 +1049,7 @@ static int segmented_read(struct x86_emulate_ctxt *ctxt,
int rc;
ulong linear;
- rc = linearize(ctxt, addr, size, false, &linear);
+ rc = linearize(ctxt, addr, size, false, false, &linear);
if (rc != X86EMUL_CONTINUE)
return rc;
return read_emulated(ctxt, ctxt->ops, linear, data, size);
@@ -1061,7 +1063,7 @@ static int segmented_write(struct x86_emulate_ctxt *ctxt,
int rc;
ulong linear;
- rc = linearize(ctxt, addr, size, true, &linear);
+ rc = linearize(ctxt, addr, size, true, false, &linear);
if (rc != X86EMUL_CONTINUE)
return rc;
return ctxt->ops->write_emulated(linear, data, size,
@@ -1076,7 +1078,7 @@ static int segmented_cmpxchg(struct x86_emulate_ctxt *ctxt,
int rc;
ulong linear;
- rc = linearize(ctxt, addr, size, true, &linear);
+ rc = linearize(ctxt, addr, size, true, false, &linear);
if (rc != X86EMUL_CONTINUE)
return rc;
return ctxt->ops->cmpxchg_emulated(linear, orig_data, data,
@@ -2576,7 +2578,7 @@ static int em_invlpg(struct x86_emulate_ctxt *ctxt)
int rc;
ulong linear;
- rc = linearize(ctxt, c->src.addr.mem, 1, false, &linear);
+ rc = linearize(ctxt, c->src.addr.mem, 1, false, false, &linear);
if (rc == X86EMUL_CONTINUE)
emulate_invlpg(ctxt->vcpu, linear);
/* Disable writeback. */
@@ -3154,7 +3156,6 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
c->fetch.end = c->fetch.start + insn_len;
if (insn_len > 0)
memcpy(c->fetch.data, insn, insn_len);
- ctxt->cs_base = seg_base(ctxt, ops, VCPU_SREG_CS);
switch (mode) {
case X86EMUL_MODE_REAL:
--
1.7.2.43.g36c08.dirty
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