Re: [PATCH] target/i386: skip kvm_msr_entry_add when kvm_vmx_basic is 0

2019-12-06 Thread no-reply 
Patchew URL: 
https://patchew.org/QEMU/1575627817-24625-1-git-send-email-catherine.h...@gmail.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Subject: [PATCH] target/i386: skip kvm_msr_entry_add when kvm_vmx_basic is 0
Type: series
Message-id: 1575627817-24625-1-git-send-email-catherine.h...@gmail.com

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
987441f target/i386: skip kvm_msr_entry_add when kvm_vmx_basic is 0

=== OUTPUT BEGIN ===
ERROR: code indent should never use tabs
#38: FILE: target/i386/kvm.c:2637:
+^I/* Only add the entry when host supports it */$

total: 1 errors, 0 warnings, 14 lines checked

Commit 987441f7424c (target/i386: skip kvm_msr_entry_add when kvm_vmx_basic is 
0) has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/1575627817-24625-1-git-send-email-catherine.h...@gmail.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-de...@redhat.com

[PATCH] target/i386: skip kvm_msr_entry_add when kvm_vmx_basic is 0

2019-12-06 Thread Catherine Ho 
Commit 1389309c811b ("KVM: nVMX: expose VMX capabilities for nested
hypervisors to userspace") expands the msr_based_features with
MSR_IA32_VMX_BASIC and others. Then together with an old kernel before
1389309c811b, the qemu call KVM_GET_MSR_FEATURE_INDEX_LIST and got the
smaller kvm_feature_msrs. Then in kvm_arch_get_supported_msr_feature(),
searching VMX_BASIC will be failed and return 0. At last kvm_vmx_basic
will be assigned to 0.

Without this patch, it will cause a qemu crash (host kernel 4.15
ubuntu 18.04+qemu 4.1):
qemu-system-x86_64: error: failed to set MSR 0x480 to 0x0
target/i386/kvm.c:2932: kvm_put_msrs: Assertion `ret ==
cpu->kvm_msr_buf->nmsrs' failed.

This fixes it by skipping kvm_msr_entry_add when kvm_vmx_basic is 0

Cc: Paolo Bonzini 
Signed-off-by: Catherine Ho 
---
 target/i386/kvm.c |7 ++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index a8c44bf..8cf84a2 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -2632,8 +2632,13 @@ static void kvm_msr_entry_add_vmx(X86CPU *cpu, 
FeatureWordArray f)
  f[FEAT_VMX_SECONDARY_CTLS]));
 kvm_msr_entry_add(cpu, MSR_IA32_VMX_EPT_VPID_CAP,
   f[FEAT_VMX_EPT_VPID_CAPS] | fixed_vmx_ept_vpid);
-kvm_msr_entry_add(cpu, MSR_IA32_VMX_BASIC,
+
+if (kvm_vmx_basic) {
+   /* Only add the entry when host supports it */
+kvm_msr_entry_add(cpu, MSR_IA32_VMX_BASIC,
   f[FEAT_VMX_BASIC] | fixed_vmx_basic);
+}
+
 kvm_msr_entry_add(cpu, MSR_IA32_VMX_MISC,
   f[FEAT_VMX_MISC] | fixed_vmx_misc);
 if (has_msr_vmx_vmfunc) {
-- 
1.7.1

Re: [PATCH] target/i386: skip kvm_msr_entry_add when kvm_vmx_basic is 0

2019-12-06 Thread Paolo Bonzini 
On 06/12/19 11:23, Catherine Ho wrote:
> Commit 1389309c811b ("KVM: nVMX: expose VMX capabilities for nested
> hypervisors to userspace") expands the msr_based_features with
> MSR_IA32_VMX_BASIC and others. Then together with an old kernel before
> 1389309c811b, the qemu call KVM_GET_MSR_FEATURE_INDEX_LIST and got the
> smaller kvm_feature_msrs. Then in kvm_arch_get_supported_msr_feature(),
> searching VMX_BASIC will be failed and return 0. At last kvm_vmx_basic
> will be assigned to 0.
> 
> Without this patch, it will cause a qemu crash (host kernel 4.15
> ubuntu 18.04+qemu 4.1):
> qemu-system-x86_64: error: failed to set MSR 0x480 to 0x0
> target/i386/kvm.c:2932: kvm_put_msrs: Assertion `ret ==
> cpu->kvm_msr_buf->nmsrs' failed.
> 
> This fixes it by skipping kvm_msr_entry_add when kvm_vmx_basic is 0
> 
> Cc: Paolo Bonzini 
> Signed-off-by: Catherine Ho 
> ---
>  target/i386/kvm.c |7 ++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index a8c44bf..8cf84a2 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -2632,8 +2632,13 @@ static void kvm_msr_entry_add_vmx(X86CPU *cpu, 
> FeatureWordArray f)
>   f[FEAT_VMX_SECONDARY_CTLS]));
>  kvm_msr_entry_add(cpu, MSR_IA32_VMX_EPT_VPID_CAP,
>f[FEAT_VMX_EPT_VPID_CAPS] | fixed_vmx_ept_vpid);
> -kvm_msr_entry_add(cpu, MSR_IA32_VMX_BASIC,
> +
> +if (kvm_vmx_basic) {
> + /* Only add the entry when host supports it */
> +kvm_msr_entry_add(cpu, MSR_IA32_VMX_BASIC,
>f[FEAT_VMX_BASIC] | fixed_vmx_basic);
> +}
> +
>  kvm_msr_entry_add(cpu, MSR_IA32_VMX_MISC,
>f[FEAT_VMX_MISC] | fixed_vmx_misc);
>  if (has_msr_vmx_vmfunc) {
> 

Yang Zhong from Intel also sent a similar patch.  Thanks very much to
both of you.

Paolo

Re: [PATCH] target/i386: skip kvm_msr_entry_add when kvm_vmx_basic is 0

2019-12-06 Thread Catherine Ho 
Hi Paolo and Eduardo
I digged into the put msr assertion bug a little more, and seems I
found the root cause.
Please have a review.

Best regards.
Catherine

On Fri, 6 Dec 2019 at 18:25, Catherine Ho  wrote:
>
> Commit 1389309c811b ("KVM: nVMX: expose VMX capabilities for nested
> hypervisors to userspace") expands the msr_based_features with
> MSR_IA32_VMX_BASIC and others. Then together with an old kernel before
> 1389309c811b, the qemu call KVM_GET_MSR_FEATURE_INDEX_LIST and got the
> smaller kvm_feature_msrs. Then in kvm_arch_get_supported_msr_feature(),
> searching VMX_BASIC will be failed and return 0. At last kvm_vmx_basic
> will be assigned to 0.
>
> Without this patch, it will cause a qemu crash (host kernel 4.15
> ubuntu 18.04+qemu 4.1):
> qemu-system-x86_64: error: failed to set MSR 0x480 to 0x0
> target/i386/kvm.c:2932: kvm_put_msrs: Assertion `ret ==
> cpu->kvm_msr_buf->nmsrs' failed.
>
> This fixes it by skipping kvm_msr_entry_add when kvm_vmx_basic is 0
>
> Cc: Paolo Bonzini 
> Signed-off-by: Catherine Ho 
> ---
>  target/i386/kvm.c |7 ++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index a8c44bf..8cf84a2 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -2632,8 +2632,13 @@ static void kvm_msr_entry_add_vmx(X86CPU *cpu, 
> FeatureWordArray f)
>   f[FEAT_VMX_SECONDARY_CTLS]));
>  kvm_msr_entry_add(cpu, MSR_IA32_VMX_EPT_VPID_CAP,
>f[FEAT_VMX_EPT_VPID_CAPS] | fixed_vmx_ept_vpid);
> -kvm_msr_entry_add(cpu, MSR_IA32_VMX_BASIC,
> +
> +if (kvm_vmx_basic) {
> +   /* Only add the entry when host supports it */
> +kvm_msr_entry_add(cpu, MSR_IA32_VMX_BASIC,
>f[FEAT_VMX_BASIC] | fixed_vmx_basic);
> +}
> +
>  kvm_msr_entry_add(cpu, MSR_IA32_VMX_MISC,
>f[FEAT_VMX_MISC] | fixed_vmx_misc);
>  if (has_msr_vmx_vmfunc) {
> --
> 1.7.1
>