* [PATCH 0/2] Add missing trace points in emulator path
@ 2022-07-28 8:25 Hou Wenlong
2022-07-28 8:25 ` [PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed Hou Wenlong
2022-07-28 8:25 ` [PATCH 2/2] KVM: x86: Add missing trace points for RDMSR/WRMSR in emulator path Hou Wenlong
0 siblings, 2 replies; 6+ messages in thread
From: Hou Wenlong @ 2022-07-28 8:25 UTC (permalink / raw)
To: kvm
Some existed trace points are missing in emulator path, e.g.,
RDMSR/WRMSR emulation and CR read/write emulation. However,
if add those trace points in emulator common interfaces in
arch/x86/kvm/x86.c, other instruction emulation may use those
interfaces too and cause too much trace records. But add those
trace points in em_* functions in arch/x86/kvm/emulate.c seems
to be ugly. Luckily, RDMSR/WRMSR emulation uses a sepreate
interface, so add trace points for RDMSR/WRMSR in emulator
path is acceptable like normal path.
Hou Wenlong (2):
KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed
KVM: x86: Add missing trace points for RDMSR/WRMSR in emulator path
arch/x86/kvm/x86.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
--
2.31.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed
2022-07-28 8:25 [PATCH 0/2] Add missing trace points in emulator path Hou Wenlong
@ 2022-07-28 8:25 ` Hou Wenlong
2022-08-30 18:44 ` Sean Christopherson
2022-07-28 8:25 ` [PATCH 2/2] KVM: x86: Add missing trace points for RDMSR/WRMSR in emulator path Hou Wenlong
1 sibling, 1 reply; 6+ messages in thread
From: Hou Wenlong @ 2022-07-28 8:25 UTC (permalink / raw)
To: kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, linux-kernel
The return value of emulator_{get|set}_mst_with_filter()
is confused, since msr access error and emulator error
are mixed. Although, KVM_MSR_RET_* doesn't conflict with
X86EMUL_IO_NEEDED at present, it is better to convert
msr access error to emulator error if error value is
needed.
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
---
arch/x86/kvm/x86.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5366f884e9a7..8df89b9c212f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7908,11 +7908,12 @@ static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
int r;
r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
-
- if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
- complete_emulated_rdmsr, r)) {
- /* Bounce to user space */
- return X86EMUL_IO_NEEDED;
+ if (r) {
+ if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
+ complete_emulated_rdmsr, r))
+ r = X86EMUL_IO_NEEDED;
+ else
+ r = X86EMUL_UNHANDLEABLE;
}
return r;
@@ -7925,11 +7926,12 @@ static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
int r;
r = kvm_set_msr_with_filter(vcpu, msr_index, data);
-
- if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
- complete_emulated_msr_access, r)) {
- /* Bounce to user space */
- return X86EMUL_IO_NEEDED;
+ if (r > 0) {
+ if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
+ complete_emulated_msr_access, r))
+ r = X86EMUL_IO_NEEDED;
+ else
+ r = X86EMUL_UNHANDLEABLE;
}
return r;
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] KVM: x86: Add missing trace points for RDMSR/WRMSR in emulator path
2022-07-28 8:25 [PATCH 0/2] Add missing trace points in emulator path Hou Wenlong
2022-07-28 8:25 ` [PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed Hou Wenlong
@ 2022-07-28 8:25 ` Hou Wenlong
2022-08-30 19:05 ` Sean Christopherson
1 sibling, 1 reply; 6+ messages in thread
From: Hou Wenlong @ 2022-07-28 8:25 UTC (permalink / raw)
To: kvm
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, linux-kernel
Since the RDMSR/WRMSR emulation uses a sepearte emualtor interface,
the trace points for RDMSR/WRMSR can be added in emulator path like
normal path.
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
---
arch/x86/kvm/x86.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8df89b9c212f..6e45b20ce9a4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7908,12 +7908,16 @@ static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
int r;
r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
- if (r) {
+ if (!r) {
+ trace_kvm_msr_read(msr_index, *pdata);
+ } else {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
- complete_emulated_rdmsr, r))
+ complete_emulated_rdmsr, r)) {
r = X86EMUL_IO_NEEDED;
- else
+ } else {
+ trace_kvm_msr_read_ex(msr_index);
r = X86EMUL_UNHANDLEABLE;
+ }
}
return r;
@@ -7926,12 +7930,16 @@ static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
int r;
r = kvm_set_msr_with_filter(vcpu, msr_index, data);
- if (r > 0) {
+ if (!r) {
+ trace_kvm_msr_write(msr_index, data);
+ } else if (r > 0) {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
- complete_emulated_msr_access, r))
+ complete_emulated_msr_access, r)) {
r = X86EMUL_IO_NEEDED;
- else
+ } else {
+ trace_kvm_msr_write_ex(msr_index, data);
r = X86EMUL_UNHANDLEABLE;
+ }
}
return r;
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed
2022-07-28 8:25 ` [PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed Hou Wenlong
@ 2022-08-30 18:44 ` Sean Christopherson
2022-08-31 3:17 ` Hou Wenlong
0 siblings, 1 reply; 6+ messages in thread
From: Sean Christopherson @ 2022-08-30 18:44 UTC (permalink / raw)
To: Hou Wenlong
Cc: kvm, Paolo Bonzini, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin, linux-kernel
On Thu, Jul 28, 2022, Hou Wenlong wrote:
> The return value of emulator_{get|set}_mst_with_filter()
> is confused, since msr access error and emulator error
> are mixed. Although, KVM_MSR_RET_* doesn't conflict with
> X86EMUL_IO_NEEDED at present, it is better to convert
> msr access error to emulator error if error value is
> needed.
>
> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> ---
> arch/x86/kvm/x86.c | 22 ++++++++++++----------
> 1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 5366f884e9a7..8df89b9c212f 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -7908,11 +7908,12 @@ static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
> int r;
>
> r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
> -
> - if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
> - complete_emulated_rdmsr, r)) {
> - /* Bounce to user space */
> - return X86EMUL_IO_NEEDED;
> + if (r) {
> + if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
> + complete_emulated_rdmsr, r))
> + r = X86EMUL_IO_NEEDED;
> + else
> + r = X86EMUL_UNHANDLEABLE;
This should be X86EMUL_PROPAGATE_FAULT, X86EMUL_UNHANDLEABLE is used to indicate
that KVM needs to bail all the way to userspace.
I definitely like the idea of converting to X86EMUL_* here instead of spreading
it across these helpers and the emulator, but in that case should convert _all_
types.
And I think it makes sense to opportunistically handle "r < 0" in the get helper.
KVM may not return -errno today, but assuming that will always hold true is
unnecessarily risking.
E.g. what about:
static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 *pdata)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
int r;
r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r) {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
complete_emulated_rdmsr, r))
return X86EMUL_IO_NEEDED;
else
return X86EMUL_PROPAGATE_FAULT;
}
return X86EMUL_CONTINUE;
}
static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 data)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
int r;
r = kvm_set_msr_with_filter(vcpu, msr_index, data);
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r) {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
complete_emulated_msr_access, r))
return X86EMUL_IO_NEEDED;
else
return X86EMUL_PROPAGATE_FAULT;
}
return X86EMUL_CONTINUE;
}
Or maybe even add a helper to do the translation? Can't tell if this is a net
positive or not. It's a bit gratuitous, but it does ensure consistent behavior
for RDMSR vs. WRMSR.
static int emulator_handle_msr_return(struct kvm_vcpu *vcpu *, int r,
u32 msr, u64 data, u32 exit_reason,
int (*comp)(struct kvm_vcpu *vcpu))
{
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r) {
if (kvm_msr_user_space(vcpu, msr, exit_reason, data, comp, r))
return X86EMUL_IO_NEEDED;
else
return X86EMUL_UNHANDLEABLE;
}
return X86EMUL_CONTINUE;
}
static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 *pdata)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
int r;
r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
return emulator_handle_msr_return(vcpu, r, msr_index, 0,
KVM_EXIT_X86_RDMSR,
complete_emulated_rdmsr);
}
static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 data)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
int r;
r = kvm_set_msr_with_filter(vcpu, msr_index, data);
return emulator_handle_msr_return(vcpu, r, msr_index, data,
KVM_EXIT_X86_WRMSR,
complete_emulated_msr_access);
}
And then the emulator side of things can be:
static int em_wrmsr(struct x86_emulate_ctxt *ctxt)
{
u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX);
u64 msr_data;
int r;
msr_data = (u32)reg_read(ctxt, VCPU_REGS_RAX)
| ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32);
r = ctxt->ops->set_msr_with_filter(ctxt, msr_index, msr_data);
if (r == X86EMUL_PROPAGATE_FAULT)
return emulate_gp(ctxt, 0);
return r;
}
static int em_rdmsr(struct x86_emulate_ctxt *ctxt)
{
u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX);
u64 msr_data;
int r;
r = ctxt->ops->get_msr_with_filter(ctxt, msr_index, &msr_data);
if (r == X86EMUL_PROPAGATE_FAULT)
return emulate_gp(ctxt, 0);
if (r == X86EMUL_CONTINUE) {
*reg_write(ctxt, VCPU_REGS_RAX) = (u32)msr_data;
*reg_write(ctxt, VCPU_REGS_RDX) = msr_data >> 32;
}
return r;
}
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] KVM: x86: Add missing trace points for RDMSR/WRMSR in emulator path
2022-07-28 8:25 ` [PATCH 2/2] KVM: x86: Add missing trace points for RDMSR/WRMSR in emulator path Hou Wenlong
@ 2022-08-30 19:05 ` Sean Christopherson
0 siblings, 0 replies; 6+ messages in thread
From: Sean Christopherson @ 2022-08-30 19:05 UTC (permalink / raw)
To: Hou Wenlong
Cc: kvm, Paolo Bonzini, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin, linux-kernel
On Thu, Jul 28, 2022, Hou Wenlong wrote:
> Since the RDMSR/WRMSR emulation uses a sepearte emualtor interface,
> the trace points for RDMSR/WRMSR can be added in emulator path like
> normal path.
>
> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> ---
> arch/x86/kvm/x86.c | 20 ++++++++++++++------
> 1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 8df89b9c212f..6e45b20ce9a4 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -7908,12 +7908,16 @@ static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
> int r;
>
> r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
> - if (r) {
> + if (!r) {
> + trace_kvm_msr_read(msr_index, *pdata);
> + } else {
> if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
> - complete_emulated_rdmsr, r))
> + complete_emulated_rdmsr, r)) {
> r = X86EMUL_IO_NEEDED;
> - else
> + } else {
> + trace_kvm_msr_read_ex(msr_index);
Drat, I suspected this patch would make adding a helper a mess. We could use
trace_kvm_msr() directly, using @exit_reason to select between "rdmsr" and "wrmsr",
but I think the end result is less readable and not worth the small amount
of deduplication. E.g. this is rather hard to read.
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r) {
if (kvm_msr_user_space(vcpu, msr, exit_reason, data, comp, r))
return X86EMUL_IO_NEEDED;
trace_kvm_msr(exit_reason == KVM_EXIT_X86_WRMSR,
msr, data, true);
return X86EMUL_PROPAGATE_FAULT;
}
trace_kvm_msr(exit_reason == KVM_EXIT_X86_WRMSR, msr, data, false);
return X86EMUL_CONTINUE;
Aha! If there "error" paths return directly, then the "else" paths go away and
this is all (IMO) a bit cleaner. And the diff for this patch should be much
smaller since there won't be any curly brace changes.
How about this for a final product?
static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 *pdata)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
int r;
r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r) {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
complete_emulated_rdmsr, r))
return X86EMUL_IO_NEEDED;
trace_kvm_msr_read_ex(msr_index);
return X86EMUL_PROPAGATE_FAULT;
}
trace_kvm_msr_read(msr_index, *pdata);
return X86EMUL_CONTINUE;
}
static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
u32 msr_index, u64 data)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
int r;
r = kvm_set_msr_with_filter(vcpu, msr_index, data);
if (r < 0)
return X86EMUL_UNHANDLEABLE;
if (r) {
if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
complete_emulated_msr_access, r))
return X86EMUL_IO_NEEDED;
trace_kvm_msr_write_ex(msr_index, data);
return X86EMUL_PROPAGATE_FAULT;
}
trace_kvm_msr_write(msr_index, data);
return X86EMUL_CONTINUE;
}
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed
2022-08-30 18:44 ` Sean Christopherson
@ 2022-08-31 3:17 ` Hou Wenlong
0 siblings, 0 replies; 6+ messages in thread
From: Hou Wenlong @ 2022-08-31 3:17 UTC (permalink / raw)
To: Sean Christopherson
Cc: kvm, Paolo Bonzini, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin, linux-kernel
On Wed, Aug 31, 2022 at 02:44:08AM +0800, Sean Christopherson wrote:
> On Thu, Jul 28, 2022, Hou Wenlong wrote:
> > The return value of emulator_{get|set}_mst_with_filter()
> > is confused, since msr access error and emulator error
> > are mixed. Although, KVM_MSR_RET_* doesn't conflict with
> > X86EMUL_IO_NEEDED at present, it is better to convert
> > msr access error to emulator error if error value is
> > needed.
> >
> > Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> > ---
> > arch/x86/kvm/x86.c | 22 ++++++++++++----------
> > 1 file changed, 12 insertions(+), 10 deletions(-)
> >
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 5366f884e9a7..8df89b9c212f 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -7908,11 +7908,12 @@ static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
> > int r;
> >
> > r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
> > -
> > - if (r && kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
> > - complete_emulated_rdmsr, r)) {
> > - /* Bounce to user space */
> > - return X86EMUL_IO_NEEDED;
> > + if (r) {
> > + if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
> > + complete_emulated_rdmsr, r))
> > + r = X86EMUL_IO_NEEDED;
> > + else
> > + r = X86EMUL_UNHANDLEABLE;
>
> This should be X86EMUL_PROPAGATE_FAULT, X86EMUL_UNHANDLEABLE is used to indicate
> that KVM needs to bail all the way to userspace.
>
> I definitely like the idea of converting to X86EMUL_* here instead of spreading
> it across these helpers and the emulator, but in that case should convert _all_
> types.
>
> And I think it makes sense to opportunistically handle "r < 0" in the get helper.
> KVM may not return -errno today, but assuming that will always hold true is
> unnecessarily risking.
I agree. The original commit 7dffecaf4eab wanted to report negative values to
userspace, but the emulator actually didn't propagate -errno to the caller.
So handling "r < 0" in the set helper is better, then only X86EMUL_* is returned.
>
> E.g. what about:
>
>
> static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
> u32 msr_index, u64 *pdata)
> {
> struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
> int r;
>
> r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
> if (r < 0)
> return X86EMUL_UNHANDLEABLE;
>
> if (r) {
> if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_RDMSR, 0,
> complete_emulated_rdmsr, r))
> return X86EMUL_IO_NEEDED;
> else
> return X86EMUL_PROPAGATE_FAULT;
> }
>
> return X86EMUL_CONTINUE;
> }
>
> static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
> u32 msr_index, u64 data)
> {
> struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
> int r;
>
> r = kvm_set_msr_with_filter(vcpu, msr_index, data);
> if (r < 0)
> return X86EMUL_UNHANDLEABLE;
>
> if (r) {
> if (kvm_msr_user_space(vcpu, msr_index, KVM_EXIT_X86_WRMSR, data,
> complete_emulated_msr_access, r))
> return X86EMUL_IO_NEEDED;
> else
> return X86EMUL_PROPAGATE_FAULT;
> }
>
> return X86EMUL_CONTINUE;
> }
>
I'll take this in the v2. Thanks.
>
> Or maybe even add a helper to do the translation? Can't tell if this is a net
> positive or not. It's a bit gratuitous, but it does ensure consistent behavior
> for RDMSR vs. WRMSR.
>
> static int emulator_handle_msr_return(struct kvm_vcpu *vcpu *, int r,
> u32 msr, u64 data, u32 exit_reason,
> int (*comp)(struct kvm_vcpu *vcpu))
> {
> if (r < 0)
> return X86EMUL_UNHANDLEABLE;
>
> if (r) {
> if (kvm_msr_user_space(vcpu, msr, exit_reason, data, comp, r))
> return X86EMUL_IO_NEEDED;
> else
> return X86EMUL_UNHANDLEABLE;
> }
>
> return X86EMUL_CONTINUE;
> }
>
> static int emulator_get_msr_with_filter(struct x86_emulate_ctxt *ctxt,
> u32 msr_index, u64 *pdata)
> {
> struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
> int r;
>
> r = kvm_get_msr_with_filter(vcpu, msr_index, pdata);
> return emulator_handle_msr_return(vcpu, r, msr_index, 0,
> KVM_EXIT_X86_RDMSR,
> complete_emulated_rdmsr);
> }
>
> static int emulator_set_msr_with_filter(struct x86_emulate_ctxt *ctxt,
> u32 msr_index, u64 data)
> {
> struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
> int r;
>
> r = kvm_set_msr_with_filter(vcpu, msr_index, data);
> return emulator_handle_msr_return(vcpu, r, msr_index, data,
> KVM_EXIT_X86_WRMSR,
> complete_emulated_msr_access);
> }
>
>
> And then the emulator side of things can be:
>
> static int em_wrmsr(struct x86_emulate_ctxt *ctxt)
> {
> u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX);
> u64 msr_data;
> int r;
>
> msr_data = (u32)reg_read(ctxt, VCPU_REGS_RAX)
> | ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32);
> r = ctxt->ops->set_msr_with_filter(ctxt, msr_index, msr_data);
>
> if (r == X86EMUL_PROPAGATE_FAULT)
> return emulate_gp(ctxt, 0);
>
> return r;
> }
>
> static int em_rdmsr(struct x86_emulate_ctxt *ctxt)
> {
> u64 msr_index = reg_read(ctxt, VCPU_REGS_RCX);
> u64 msr_data;
> int r;
>
> r = ctxt->ops->get_msr_with_filter(ctxt, msr_index, &msr_data);
>
> if (r == X86EMUL_PROPAGATE_FAULT)
> return emulate_gp(ctxt, 0);
>
> if (r == X86EMUL_CONTINUE) {
> *reg_write(ctxt, VCPU_REGS_RAX) = (u32)msr_data;
> *reg_write(ctxt, VCPU_REGS_RDX) = msr_data >> 32;
> }
> return r;
> }
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-08-31 3:18 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-07-28 8:25 [PATCH 0/2] Add missing trace points in emulator path Hou Wenlong
2022-07-28 8:25 ` [PATCH 1/2] KVM: x86: Return emulator error if RDMSR/WRMSR emulation failed Hou Wenlong
2022-08-30 18:44 ` Sean Christopherson
2022-08-31 3:17 ` Hou Wenlong
2022-07-28 8:25 ` [PATCH 2/2] KVM: x86: Add missing trace points for RDMSR/WRMSR in emulator path Hou Wenlong
2022-08-30 19:05 ` Sean Christopherson
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.