[Qemu-devel] [PULL 0/4] x86 queue, 2018-12-11

[Qemu-devel] [PULL 0/4] x86 queue, 2018-12-11

[Eduardo Habkost]

The following changes since commit 32a1a94dd324d33578dca1dc96d7896a0244d768:

  Update version for v3.1.0 release (2018-12-11 17:18:37 +0000)

are available in the Git repository at:

  git://github.com/ehabkost/qemu.git tags/x86-next-pull-request

for you to fetch changes up to 0e8916582991b9fd0b94850a8444b8b80d0a0955:

  i386: Add "stibp" flag name (2018-12-11 18:50:48 -0200)

----------------------------------------------------------------
x86 queue, 2018-12-11

* New CPU features: MOVDIRI, MOVDIR64B (Liu Jingqi);
  STIBP (Eduardo Habkost)
* Fix clang build warning (Peter Maydell)

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

Eduardo Habkost (1):
  i386: Add "stibp" flag name

Liu Jingqi (2):
  x86/cpu: Enable MOVDIRI cpu feature
  x86/cpu: Enable MOVDIR64B cpu feature

Peter Maydell (1):
  target/i386/kvm.c: Don't mark cpuid_data as QEMU_PACKED

 target/i386/cpu.h |  2 ++
 target/i386/cpu.c |  6 +++---
 target/i386/kvm.c | 10 +++++++++-
 3 files changed, 14 insertions(+), 4 deletions(-)

-- 
2.18.0.rc1.1.g3f1ff2140

[Qemu-devel] [PULL 1/4] x86/cpu: Enable MOVDIRI cpu feature

[Eduardo Habkost]

From: Liu Jingqi <jingqi.liu@intel.com>

MOVDIRI moves doubleword or quadword from register to memory through
direct store which is implemented by using write combining (WC) for
writing data directly into memory without caching the data.

The bit definition:
CPUID.(EAX=7,ECX=0):ECX[bit 27] MOVDIRI

The release document ref below link:
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf

Cc: Xu Tao <tao3.xu@intel.com>
Signed-off-by: Liu Jingqi <jingqi.liu@intel.com>
Message-Id: <1541488407-17045-2-git-send-email-jingqi.liu@intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.h | 1 +
 target/i386/cpu.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 9c52d0cbeb..b4f03ffd74 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -687,6 +687,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 #define CPUID_7_0_ECX_LA57     (1U << 16)
 #define CPUID_7_0_ECX_RDPID    (1U << 22)
 #define CPUID_7_0_ECX_CLDEMOTE (1U << 25)  /* CLDEMOTE Instruction */
+#define CPUID_7_0_ECX_MOVDIRI  (1U << 27)  /* MOVDIRI Instruction */
 
 #define CPUID_7_0_EDX_AVX512_4VNNIW (1U << 2) /* AVX512 Neural Network Instructions */
 #define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply Accumulation Single Precision */
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index f81d35e1f9..227baea337 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1023,7 +1023,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             "avx512bitalg", NULL, "avx512-vpopcntdq", NULL,
             "la57", NULL, NULL, NULL,
             NULL, NULL, "rdpid", NULL,
-            NULL, "cldemote", NULL, NULL,
+            NULL, "cldemote", NULL, "movdiri",
             NULL, NULL, NULL, NULL,
         },
         .cpuid = {
-- 
2.18.0.rc1.1.g3f1ff2140

[Qemu-devel] [PULL 2/4] x86/cpu: Enable MOVDIR64B cpu feature

[Eduardo Habkost]

From: Liu Jingqi <jingqi.liu@intel.com>

MOVDIR64B moves 64-bytes as direct-store with 64-bytes write atomicity.
Direct store is implemented by using write combining (WC) for writing
data directly into memory without caching the data.

The bit definition:
CPUID.(EAX=7,ECX=0):ECX[bit 28] MOVDIR64B

The release document ref below link:
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf

Cc: Xu Tao <tao3.xu@intel.com>
Signed-off-by: Liu Jingqi <jingqi.liu@intel.com>
Message-Id: <1541488407-17045-3-git-send-email-jingqi.liu@intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.h | 1 +
 target/i386/cpu.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index b4f03ffd74..ef41a033c5 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -688,6 +688,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 #define CPUID_7_0_ECX_RDPID    (1U << 22)
 #define CPUID_7_0_ECX_CLDEMOTE (1U << 25)  /* CLDEMOTE Instruction */
 #define CPUID_7_0_ECX_MOVDIRI  (1U << 27)  /* MOVDIRI Instruction */
+#define CPUID_7_0_ECX_MOVDIR64B (1U << 28) /* MOVDIR64B Instruction */
 
 #define CPUID_7_0_EDX_AVX512_4VNNIW (1U << 2) /* AVX512 Neural Network Instructions */
 #define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply Accumulation Single Precision */
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 227baea337..86a934d450 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1024,7 +1024,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             "la57", NULL, NULL, NULL,
             NULL, NULL, "rdpid", NULL,
             NULL, "cldemote", NULL, "movdiri",
-            NULL, NULL, NULL, NULL,
+            "movdir64b", NULL, NULL, NULL,
         },
         .cpuid = {
             .eax = 7,
-- 
2.18.0.rc1.1.g3f1ff2140

[Qemu-devel] [PULL 3/4] target/i386/kvm.c: Don't mark cpuid_data as QEMU_PACKED

[Eduardo Habkost]

From: Peter Maydell <peter.maydell@linaro.org>

clang complains about taking the address of a packed
member of a struct:

target/i386/kvm.c:1245:27: warning: taking address of packed member 'cpuid' of class or structure '' may result in an unaligned pointer value [-Waddress-of-packed-member]
    c = cpuid_find_entry(&cpuid_data.cpuid, 1, 0);
                          ^~~~~~~~~~~~~~~~
target/i386/kvm.c:1297:31: warning: taking address of packed member 'cpuid' of class or structure '' may result in an unaligned pointer value [-Waddress-of-packed-member]
        c = cpuid_find_entry(&cpuid_data.cpuid, kvm_base, 0);
                              ^~~~~~~~~~~~~~~~

The kernel's definitions of struct kvm_cpuid2 and struct
kvm_cpuid_entry2 are carefully set up with padding fields
so that there is no between-struct padding anyway, so
the QEMU_PACKED annotation is unnecessary and might result
in the compiler generating worse code. Drop it, and instead
assert at build time that there is no stray padding.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20181210114654.31433-1-peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/kvm.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index b2401d13ea..739cf8c8ea 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -864,7 +864,15 @@ int kvm_arch_init_vcpu(CPUState *cs)
     struct {
         struct kvm_cpuid2 cpuid;
         struct kvm_cpuid_entry2 entries[KVM_MAX_CPUID_ENTRIES];
-    } QEMU_PACKED cpuid_data;
+    } cpuid_data;
+    /*
+     * The kernel defines these structs with padding fields so there
+     * should be no extra padding in our cpuid_data struct.
+     */
+    QEMU_BUILD_BUG_ON(sizeof(cpuid_data) !=
+                      sizeof(struct kvm_cpuid2) +
+                      sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES);
+
     X86CPU *cpu = X86_CPU(cs);
     CPUX86State *env = &cpu->env;
     uint32_t limit, i, j, cpuid_i;
-- 
2.18.0.rc1.1.g3f1ff2140

[Qemu-devel] [PULL 4/4] i386: Add "stibp" flag name

[Eduardo Habkost]

The STIBP flag may be supported by the host KVM module, so QEMU
can allow it to be configured manually, and it can be exposed to
guests when using "-cpu host".

No additional migration code is required because the whole
contents of spec_ctrl is already migrated in the "cpu/spec_ctrl"
section.

Corresponding KVM patch was submitted at:
https://lore.kernel.org/lkml/20181205191956.31480-1-ehabkost@redhat.com/

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20181210180250.31299-1-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 86a934d450..12f559b6af 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1042,7 +1042,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             NULL, NULL, NULL, NULL,
             NULL, NULL, "pconfig", NULL,
             NULL, NULL, NULL, NULL,
-            NULL, NULL, "spec-ctrl", NULL,
+            NULL, NULL, "spec-ctrl", "stibp",
             NULL, "arch-capabilities", NULL, "ssbd",
         },
         .cpuid = {
-- 
2.18.0.rc1.1.g3f1ff2140

Re: [Qemu-devel] [PULL 4/4] i386: Add "stibp" flag name

[Lendacky, Thomas]

On 12/11/2018 02:53 PM, Eduardo Habkost wrote:
> The STIBP flag may be supported by the host KVM module, so QEMU
> can allow it to be configured manually, and it can be exposed to
> guests when using "-cpu host".
> 
> No additional migration code is required because the whole
> contents of spec_ctrl is already migrated in the "cpu/spec_ctrl"
> section.
> 
> Corresponding KVM patch was submitted at:
> https://lore.kernel.org/lkml/20181205191956.31480-1-ehabkost@redhat.com/
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> Message-Id: <20181210180250.31299-1-ehabkost@redhat.com>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  target/i386/cpu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 86a934d450..12f559b6af 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -1042,7 +1042,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>              NULL, NULL, NULL, NULL,
>              NULL, NULL, "pconfig", NULL,
>              NULL, NULL, NULL, NULL,
> -            NULL, NULL, "spec-ctrl", NULL,
> +            NULL, NULL, "spec-ctrl", "stibp",

I guess I missed this earlier. Is there a corresponding patch for the AMD
STIBP bit (CPUID 0x80000008_EBX[15]) that is in KVM?

Thanks,
Tom

>              NULL, "arch-capabilities", NULL, "ssbd",
>          },
>          .cpuid = {
> 

Re: [Qemu-devel] [PULL 4/4] i386: Add "stibp" flag name

[Daniel P. Berrangé]

On Wed, Dec 12, 2018 at 04:57:42PM +0000, Lendacky, Thomas wrote:
> On 12/11/2018 02:53 PM, Eduardo Habkost wrote:
> > The STIBP flag may be supported by the host KVM module, so QEMU
> > can allow it to be configured manually, and it can be exposed to
> > guests when using "-cpu host".
> > 
> > No additional migration code is required because the whole
> > contents of spec_ctrl is already migrated in the "cpu/spec_ctrl"
> > section.
> > 
> > Corresponding KVM patch was submitted at:
> > https://lore.kernel.org/lkml/20181205191956.31480-1-ehabkost@redhat.com/
> > 
> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> > Message-Id: <20181210180250.31299-1-ehabkost@redhat.com>
> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> > ---
> >  target/i386/cpu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > index 86a934d450..12f559b6af 100644
> > --- a/target/i386/cpu.c
> > +++ b/target/i386/cpu.c
> > @@ -1042,7 +1042,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> >              NULL, NULL, NULL, NULL,
> >              NULL, NULL, "pconfig", NULL,
> >              NULL, NULL, NULL, NULL,
> > -            NULL, NULL, "spec-ctrl", NULL,
> > +            NULL, NULL, "spec-ctrl", "stibp",
> 
> I guess I missed this earlier. Is there a corresponding patch for the AMD
> STIBP bit (CPUID 0x80000008_EBX[15]) that is in KVM?

This Intel STIBP patch is one that many distros have carried downstream
since the flaw came to light.

I've not seen any equiv patch for AMD STIBP bit, in either QMEU or libvirt,
so guess that's a gap that needs filling.

Regards,
Daniel
-- 
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Re: [Qemu-devel] [PULL 4/4] i386: Add "stibp" flag name

[Eduardo Habkost]

On Wed, Dec 12, 2018 at 05:01:10PM +0000, Daniel P. Berrangé wrote:
> On Wed, Dec 12, 2018 at 04:57:42PM +0000, Lendacky, Thomas wrote:
> > On 12/11/2018 02:53 PM, Eduardo Habkost wrote:
> > > The STIBP flag may be supported by the host KVM module, so QEMU
> > > can allow it to be configured manually, and it can be exposed to
> > > guests when using "-cpu host".
> > > 
> > > No additional migration code is required because the whole
> > > contents of spec_ctrl is already migrated in the "cpu/spec_ctrl"
> > > section.
> > > 
> > > Corresponding KVM patch was submitted at:
> > > https://lore.kernel.org/lkml/20181205191956.31480-1-ehabkost@redhat.com/
> > > 
> > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> > > Message-Id: <20181210180250.31299-1-ehabkost@redhat.com>
> > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> > > ---
> > >  target/i386/cpu.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > > index 86a934d450..12f559b6af 100644
> > > --- a/target/i386/cpu.c
> > > +++ b/target/i386/cpu.c
> > > @@ -1042,7 +1042,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> > >              NULL, NULL, NULL, NULL,
> > >              NULL, NULL, "pconfig", NULL,
> > >              NULL, NULL, NULL, NULL,
> > > -            NULL, NULL, "spec-ctrl", NULL,
> > > +            NULL, NULL, "spec-ctrl", "stibp",
> > 
> > I guess I missed this earlier. Is there a corresponding patch for the AMD
> > STIBP bit (CPUID 0x80000008_EBX[15]) that is in KVM?
> 
> This Intel STIBP patch is one that many distros have carried downstream
> since the flaw came to light.
> 
> I've not seen any equiv patch for AMD STIBP bit, in either QMEU or libvirt,
> so guess that's a gap that needs filling.

I can submit a "amd-stibp" patch for completeness, although I
doubt many people will actually use the flag.

-- 
Eduardo

Re: [Qemu-devel] [PULL 0/4] x86 queue, 2018-12-11

[Peter Maydell]

On Tue, 11 Dec 2018 at 20:53, Eduardo Habkost <ehabkost@redhat.com> wrote:
>
> The following changes since commit 32a1a94dd324d33578dca1dc96d7896a0244d768:
>
>   Update version for v3.1.0 release (2018-12-11 17:18:37 +0000)
>
> are available in the Git repository at:
>
>   git://github.com/ehabkost/qemu.git tags/x86-next-pull-request
>
> for you to fetch changes up to 0e8916582991b9fd0b94850a8444b8b80d0a0955:
>
>   i386: Add "stibp" flag name (2018-12-11 18:50:48 -0200)
>
> ----------------------------------------------------------------
> x86 queue, 2018-12-11
>
> * New CPU features: MOVDIRI, MOVDIR64B (Liu Jingqi);
>   STIBP (Eduardo Habkost)
> * Fix clang build warning (Peter Maydell)
>
> ----------------------------------------------------------------

Applied, thanks.

-- PMM