2019-05-08 12:18:21

by Paolo Bonzini

[permalink] [raw]
Subject: [PATCH v2] kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete

From: Aaron Lewis <[email protected]>

nested_run_pending=1 implies we have successfully entered guest mode.
Move setting from external state in vmx_set_nested_state() until after
all other checks are complete.

Based on a patch by Aaron Lewis.

Signed-off-by: Paolo Bonzini <[email protected]>
---
arch/x86/kvm/vmx/nested.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index cec77f30f61c..e58caff92694 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5420,9 +5420,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
return 0;

- vmx->nested.nested_run_pending =
- !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
-
if (nested_cpu_has_shadow_vmcs(vmcs12) &&
vmcs12->vmcs_link_pointer != -1ull) {
struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
@@ -5446,9 +5443,14 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
return -EINVAL;

vmx->nested.dirty_vmcs12 = true;
+ vmx->nested.nested_run_pending =
+ !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
+
ret = nested_vmx_enter_non_root_mode(vcpu, false);
- if (ret)
+ if (ret) {
+ vmx->nested.nested_run_pending = 0;
return -EINVAL;
+ }

return 0;
}
--
1.8.3.1


2019-05-08 14:48:31

by Sean Christopherson

[permalink] [raw]
Subject: Re: [PATCH v2] kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete

On Wed, May 08, 2019 at 02:16:39PM +0200, Paolo Bonzini wrote:
> From: Aaron Lewis <[email protected]>

If this is actually attributed to Aaron it needs his SOB.

> nested_run_pending=1 implies we have successfully entered guest mode.
> Move setting from external state in vmx_set_nested_state() until after
> all other checks are complete.

It'd be helpful to at least mention the flag is consumed by
nested_vmx_enter_non_root_mode().

> Based on a patch by Aaron Lewis.
>
> Signed-off-by: Paolo Bonzini <[email protected]>
> ---

For the code itself:

Reviewed-by: Sean Christopherson <[email protected]>

> arch/x86/kvm/vmx/nested.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index cec77f30f61c..e58caff92694 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -5420,9 +5420,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
> return 0;
>
> - vmx->nested.nested_run_pending =
> - !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> -
> if (nested_cpu_has_shadow_vmcs(vmcs12) &&
> vmcs12->vmcs_link_pointer != -1ull) {
> struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
> @@ -5446,9 +5443,14 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> return -EINVAL;
>
> vmx->nested.dirty_vmcs12 = true;
> + vmx->nested.nested_run_pending =
> + !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> +
> ret = nested_vmx_enter_non_root_mode(vcpu, false);
> - if (ret)
> + if (ret) {
> + vmx->nested.nested_run_pending = 0;
> return -EINVAL;
> + }
>
> return 0;
> }
> --
> 1.8.3.1
>

2019-05-08 18:30:27

by Sean Christopherson

[permalink] [raw]
Subject: Re: [PATCH v2] kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete

On Wed, May 08, 2019 at 10:53:12AM -0700, Aaron Lewis wrote:
> nested_run_pending is also checked in
> nested_vmx_check_vmentry_postreqs
> (https://elixir.bootlin.com/linux/v5.1/source/arch/x86/kvm/vmx/nested.c#L2709)
> so I think the setting needs to be moved to just prior to that call
> with Paolo's rollback along with another for if the prereqs and
> postreqs fail. I put a patch together below:

Gah, I missed that usage (also, it's now nested_vmx_check_guest_state()).

Side topic, I think the VM_ENTRY_LOAD_BNDCFGS check should be gated by
nested_run_pending, a la the EFER check.'

> ------------------------------------
>
> nested_run_pending=1 implies we have successfully entered guest mode.
> Move setting from external state in vmx_set_nested_state() until after
> all other checks are complete.
>
> Signed-off-by: Aaron Lewis <[email protected]>
> Reviewed-by: Peter Shier <[email protected]>
> ---
> arch/x86/kvm/vmx/nested.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 6401eb7ef19c..cf1f810223d2 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -5460,9 +5460,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
> return 0;
>
> - vmx->nested.nested_run_pending =
> - !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);

Alternatively, it might be better to leave nested_run_pending where it
is and instead add a label to handle clearing the flag on error. IIUC,
the real issue is that nested_run_pending is left set after a failed
vmx_set_nested_state(), not that its shouldn't be set in the shadow
VMCS handling.

Patch attached, though it's completely untested. The KVM selftests are
broken for me right now, grrr.

> -
> if (nested_cpu_has_shadow_vmcs(vmcs12) &&
> vmcs12->vmcs_link_pointer != -1ull) {
> struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
> @@ -5480,14 +5477,21 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> return -EINVAL;
> }
>
> + vmx->nested.nested_run_pending =
> + !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> +
> if (nested_vmx_check_vmentry_prereqs(vcpu, vmcs12) ||
> - nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual))
> + nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual)) {
> + vmx->nested.nested_run_pending = 0;
> return -EINVAL;
> + }
>
> vmx->nested.dirty_vmcs12 = true;
> ret = nested_vmx_enter_non_root_mode(vcpu, false);
> - if (ret)
> + if (ret) {
> + vmx->nested.nested_run_pending = 0;
> return -EINVAL;
> + }
>
> return 0;
> }


Attachments:
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0001-KVM-nVMX-Clear-nested_run_pending-if-setting-nested-.patch (1.99 kB)
Download all attachments

2019-05-08 20:00:50

by Aaron Lewis

[permalink] [raw]
Subject: Re: [PATCH v2] kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete

From: Sean Christopherson <[email protected]>
Date: Wed, May 8, 2019 at 7:20 AM
To: Paolo Bonzini
Cc: <[email protected]>, <[email protected]>, Peter
Shier, Aaron Lewis

> On Wed, May 08, 2019 at 02:16:39PM +0200, Paolo Bonzini wrote:
> > From: Aaron Lewis <[email protected]>
>
> If this is actually attributed to Aaron it needs his SOB.
>
> > nested_run_pending=1 implies we have successfully entered guest mode.
> > Move setting from external state in vmx_set_nested_state() until after
> > all other checks are complete.
>
> It'd be helpful to at least mention the flag is consumed by
> nested_vmx_enter_non_root_mode().
>
> > Based on a patch by Aaron Lewis.
> >
> > Signed-off-by: Paolo Bonzini <[email protected]>
> > ---
>
> For the code itself:
>
> Reviewed-by: Sean Christopherson <[email protected]>
>
> > arch/x86/kvm/vmx/nested.c | 10 ++++++----
> > 1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index cec77f30f61c..e58caff92694 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -5420,9 +5420,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> > if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
> > return 0;
> >
> > - vmx->nested.nested_run_pending =
> > - !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> > -
> > if (nested_cpu_has_shadow_vmcs(vmcs12) &&
> > vmcs12->vmcs_link_pointer != -1ull) {
> > struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
> > @@ -5446,9 +5443,14 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> > return -EINVAL;
> >
> > vmx->nested.dirty_vmcs12 = true;
> > + vmx->nested.nested_run_pending =
> > + !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> > +
> > ret = nested_vmx_enter_non_root_mode(vcpu, false);
> > - if (ret)
> > + if (ret) {
> > + vmx->nested.nested_run_pending = 0;
> > return -EINVAL;
> > + }
> >
> > return 0;
> > }
> > --
> > 1.8.3.1
> >

nested_run_pending is also checked in
nested_vmx_check_vmentry_postreqs
(https://elixir.bootlin.com/linux/v5.1/source/arch/x86/kvm/vmx/nested.c#L2709)
so I think the setting needs to be moved to just prior to that call
with Paolo's rollback along with another for if the prereqs and
postreqs fail. I put a patch together below:

------------------------------------

nested_run_pending=1 implies we have successfully entered guest mode.
Move setting from external state in vmx_set_nested_state() until after
all other checks are complete.

Signed-off-by: Aaron Lewis <[email protected]>
Reviewed-by: Peter Shier <[email protected]>
---
arch/x86/kvm/vmx/nested.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 6401eb7ef19c..cf1f810223d2 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5460,9 +5460,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
return 0;

- vmx->nested.nested_run_pending =
- !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
-
if (nested_cpu_has_shadow_vmcs(vmcs12) &&
vmcs12->vmcs_link_pointer != -1ull) {
struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
@@ -5480,14 +5477,21 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
return -EINVAL;
}

+ vmx->nested.nested_run_pending =
+ !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
+
if (nested_vmx_check_vmentry_prereqs(vcpu, vmcs12) ||
- nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual))
+ nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual)) {
+ vmx->nested.nested_run_pending = 0;
return -EINVAL;
+ }

vmx->nested.dirty_vmcs12 = true;
ret = nested_vmx_enter_non_root_mode(vcpu, false);
- if (ret)
+ if (ret) {
+ vmx->nested.nested_run_pending = 0;
return -EINVAL;
+ }

return 0;
}

2019-05-08 21:15:32

by Aaron Lewis

[permalink] [raw]
Subject: Re: [PATCH v2] kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete

From: Sean Christopherson <[email protected]>
Date: Wed, May 8, 2019 at 11:13 AM
To: Aaron Lewis
Cc: Paolo Bonzini, <[email protected]>,
<[email protected]>, Peter Shier

> On Wed, May 08, 2019 at 10:53:12AM -0700, Aaron Lewis wrote:
> > nested_run_pending is also checked in
> > nested_vmx_check_vmentry_postreqs
> > (https://elixir.bootlin.com/linux/v5.1/source/arch/x86/kvm/vmx/nested.c#L2709)
> > so I think the setting needs to be moved to just prior to that call
> > with Paolo's rollback along with another for if the prereqs and
> > postreqs fail. I put a patch together below:
>
> Gah, I missed that usage (also, it's now nested_vmx_check_guest_state()).
>
> Side topic, I think the VM_ENTRY_LOAD_BNDCFGS check should be gated by
> nested_run_pending, a la the EFER check.'
>
> > ------------------------------------
> >
> > nested_run_pending=1 implies we have successfully entered guest mode.
> > Move setting from external state in vmx_set_nested_state() until after
> > all other checks are complete.
> >
> > Signed-off-by: Aaron Lewis <[email protected]>
> > Reviewed-by: Peter Shier <[email protected]>
> > ---
> > arch/x86/kvm/vmx/nested.c | 14 +++++++++-----
> > 1 file changed, 9 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index 6401eb7ef19c..cf1f810223d2 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -5460,9 +5460,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> > if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
> > return 0;
> >
> > - vmx->nested.nested_run_pending =
> > - !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
>
> Alternatively, it might be better to leave nested_run_pending where it
> is and instead add a label to handle clearing the flag on error. IIUC,
> the real issue is that nested_run_pending is left set after a failed
> vmx_set_nested_state(), not that its shouldn't be set in the shadow
> VMCS handling.
>
> Patch attached, though it's completely untested. The KVM selftests are
> broken for me right now, grrr.
>
> > -
> > if (nested_cpu_has_shadow_vmcs(vmcs12) &&
> > vmcs12->vmcs_link_pointer != -1ull) {
> > struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
> > @@ -5480,14 +5477,21 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> > return -EINVAL;
> > }
> >
> > + vmx->nested.nested_run_pending =
> > + !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> > +
> > if (nested_vmx_check_vmentry_prereqs(vcpu, vmcs12) ||
> > - nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual))
> > + nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual)) {
> > + vmx->nested.nested_run_pending = 0;
> > return -EINVAL;
> > + }
> >
> > vmx->nested.dirty_vmcs12 = true;
> > ret = nested_vmx_enter_non_root_mode(vcpu, false);
> > - if (ret)
> > + if (ret) {
> > + vmx->nested.nested_run_pending = 0;
> > return -EINVAL;
> > + }
> >
> > return 0;
> > }

Here is an update based on your patch. I ran these changes against
the test vmx_set_nested_state_test, and it run successfully.

That's correct that we are only concerned about restoring the state of
nested_run_pending, so it's fine to set it where we do as long as we
back the state change out before returning if we get an error.

---------------------------------------------

nested_run_pending=1 implies we have successfully entered guest mode.
Move setting from external state in vmx_set_nested_state() until after
all other checks are complete.

Signed-off-by: Aaron Lewis <[email protected]>
Tested-by: Aaron Lewis <[email protected]>
Reviewed-by: Peter Shier <[email protected]>
---
arch/x86/kvm/vmx/nested.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 6401eb7ef19c..fe5814df5149 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5468,28 +5468,36 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);

if (kvm_state->size < sizeof(kvm_state) + 2 * sizeof(*vmcs12))
- return -EINVAL;
+ goto error_guest_mode_einval;

if (copy_from_user(shadow_vmcs12,
user_kvm_nested_state->data + VMCS12_SIZE,
- sizeof(*vmcs12)))
- return -EFAULT;
+ sizeof(*vmcs12))) {
+ ret = -EFAULT;
+ goto error_guest_mode;
+ }

if (shadow_vmcs12->hdr.revision_id != VMCS12_REVISION ||
!shadow_vmcs12->hdr.shadow_vmcs)
- return -EINVAL;
+ goto error_guest_mode_einval;
}

if (nested_vmx_check_vmentry_prereqs(vcpu, vmcs12) ||
nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual))
- return -EINVAL;
+ goto error_guest_mode_einval;

vmx->nested.dirty_vmcs12 = true;
ret = nested_vmx_enter_non_root_mode(vcpu, false);
if (ret)
- return -EINVAL;
+ goto error_guest_mode_einval;

return 0;
+
+error_guest_mode_einval:
+ ret = -EINVAL;
+error_guest_mode:
+ vmx->nested.nested_run_pending = 0;
+ return ret;
}

void nested_vmx_vcpu_setup(void)

2019-05-15 16:46:26

by Aaron Lewis

[permalink] [raw]
Subject: Re: [PATCH v2] kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete

On Wed, May 8, 2019 at 2:13 PM Aaron Lewis <[email protected]> wrote:
>
> From: Sean Christopherson <[email protected]>
> Date: Wed, May 8, 2019 at 11:13 AM
> To: Aaron Lewis
> Cc: Paolo Bonzini, <[email protected]>,
> <[email protected]>, Peter Shier
>
> > On Wed, May 08, 2019 at 10:53:12AM -0700, Aaron Lewis wrote:
> > > nested_run_pending is also checked in
> > > nested_vmx_check_vmentry_postreqs
> > > (https://elixir.bootlin.com/linux/v5.1/source/arch/x86/kvm/vmx/nested.c#L2709)
> > > so I think the setting needs to be moved to just prior to that call
> > > with Paolo's rollback along with another for if the prereqs and
> > > postreqs fail. I put a patch together below:
> >
> > Gah, I missed that usage (also, it's now nested_vmx_check_guest_state()).
> >
> > Side topic, I think the VM_ENTRY_LOAD_BNDCFGS check should be gated by
> > nested_run_pending, a la the EFER check.'
> >
> > > ------------------------------------
> > >
> > > nested_run_pending=1 implies we have successfully entered guest mode.
> > > Move setting from external state in vmx_set_nested_state() until after
> > > all other checks are complete.
> > >
> > > Signed-off-by: Aaron Lewis <[email protected]>
> > > Reviewed-by: Peter Shier <[email protected]>
> > > ---
> > > arch/x86/kvm/vmx/nested.c | 14 +++++++++-----
> > > 1 file changed, 9 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > > index 6401eb7ef19c..cf1f810223d2 100644
> > > --- a/arch/x86/kvm/vmx/nested.c
> > > +++ b/arch/x86/kvm/vmx/nested.c
> > > @@ -5460,9 +5460,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> > > if (!(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
> > > return 0;
> > >
> > > - vmx->nested.nested_run_pending =
> > > - !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> >
> > Alternatively, it might be better to leave nested_run_pending where it
> > is and instead add a label to handle clearing the flag on error. IIUC,
> > the real issue is that nested_run_pending is left set after a failed
> > vmx_set_nested_state(), not that its shouldn't be set in the shadow
> > VMCS handling.
> >
> > Patch attached, though it's completely untested. The KVM selftests are
> > broken for me right now, grrr.
> >
> > > -
> > > if (nested_cpu_has_shadow_vmcs(vmcs12) &&
> > > vmcs12->vmcs_link_pointer != -1ull) {
> > > struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
> > > @@ -5480,14 +5477,21 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> > > return -EINVAL;
> > > }
> > >
> > > + vmx->nested.nested_run_pending =
> > > + !!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
> > > +
> > > if (nested_vmx_check_vmentry_prereqs(vcpu, vmcs12) ||
> > > - nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual))
> > > + nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual)) {
> > > + vmx->nested.nested_run_pending = 0;
> > > return -EINVAL;
> > > + }
> > >
> > > vmx->nested.dirty_vmcs12 = true;
> > > ret = nested_vmx_enter_non_root_mode(vcpu, false);
> > > - if (ret)
> > > + if (ret) {
> > > + vmx->nested.nested_run_pending = 0;
> > > return -EINVAL;
> > > + }
> > >
> > > return 0;
> > > }
>
> Here is an update based on your patch. I ran these changes against
> the test vmx_set_nested_state_test, and it run successfully.
>
> That's correct that we are only concerned about restoring the state of
> nested_run_pending, so it's fine to set it where we do as long as we
> back the state change out before returning if we get an error.
>
> ---------------------------------------------
>
> nested_run_pending=1 implies we have successfully entered guest mode.
> Move setting from external state in vmx_set_nested_state() until after
> all other checks are complete.
>
> Signed-off-by: Aaron Lewis <[email protected]>
> Tested-by: Aaron Lewis <[email protected]>
> Reviewed-by: Peter Shier <[email protected]>
> ---
> arch/x86/kvm/vmx/nested.c | 20 ++++++++++++++------
> 1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 6401eb7ef19c..fe5814df5149 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -5468,28 +5468,36 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
> struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
>
> if (kvm_state->size < sizeof(kvm_state) + 2 * sizeof(*vmcs12))
> - return -EINVAL;
> + goto error_guest_mode_einval;
>
> if (copy_from_user(shadow_vmcs12,
> user_kvm_nested_state->data + VMCS12_SIZE,
> - sizeof(*vmcs12)))
> - return -EFAULT;
> + sizeof(*vmcs12))) {
> + ret = -EFAULT;
> + goto error_guest_mode;
> + }
>
> if (shadow_vmcs12->hdr.revision_id != VMCS12_REVISION ||
> !shadow_vmcs12->hdr.shadow_vmcs)
> - return -EINVAL;
> + goto error_guest_mode_einval;
> }
>
> if (nested_vmx_check_vmentry_prereqs(vcpu, vmcs12) ||
> nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual))
> - return -EINVAL;
> + goto error_guest_mode_einval;
>
> vmx->nested.dirty_vmcs12 = true;
> ret = nested_vmx_enter_non_root_mode(vcpu, false);
> if (ret)
> - return -EINVAL;
> + goto error_guest_mode_einval;
>
> return 0;
> +
> +error_guest_mode_einval:
> + ret = -EINVAL;
> +error_guest_mode:
> + vmx->nested.nested_run_pending = 0;
> + return ret;
> }
>
> void nested_vmx_vcpu_setup(void)

Sean, I updated this patch based on the one you sent out. Does it
look good now?