[PATCH 1/2] x86, lib: Add a wbinvd helper for an arbitrary cpu set

[PATCH 1/2] x86, lib: Add a wbinvd helper for an arbitrary cpu set

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

Add a wbinvd helper for an arbitrary set of CPUs.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/include/asm/smp.h |    4 +++-
 arch/x86/lib/cache-smp.c   |   12 ++++++++++++
 2 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 4c2f63c..f7805f1 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -141,6 +141,7 @@ void native_cpu_die(unsigned int cpu);
 void native_play_dead(void);
 void play_dead_common(void);
 void wbinvd_on_cpu(int cpu);
+void wbinvd_on_cpus(const struct cpumask *);
 int wbinvd_on_all_cpus(void);
 
 void native_send_call_func_ipi(const struct cpumask *mask);
@@ -155,7 +156,8 @@ static inline int num_booting_cpus(void)
 	return cpumask_weight(cpu_callout_mask);
 }
 #else /* !CONFIG_SMP */
-#define wbinvd_on_cpu(cpu)     wbinvd()
+#define wbinvd_on_cpu(cpu)	wbinvd()
+#define wbinvd_on_cpus(mask)	wbinvd()
 static inline int wbinvd_on_all_cpus(void)
 {
 	wbinvd();
diff --git a/arch/x86/lib/cache-smp.c b/arch/x86/lib/cache-smp.c
index a3c6688..7778d56 100644
--- a/arch/x86/lib/cache-smp.c
+++ b/arch/x86/lib/cache-smp.c
@@ -12,6 +12,18 @@ void wbinvd_on_cpu(int cpu)
 }
 EXPORT_SYMBOL(wbinvd_on_cpu);
 
+void wbinvd_on_cpus(const struct cpumask *mask)
+{
+	int this_cpu = get_cpu();
+
+	if (cpumask_test_cpu(this_cpu, mask))
+		wbinvd();
+
+	smp_call_function_many(mask, __wbinvd, NULL, 1);
+	put_cpu();
+}
+EXPORT_SYMBOL(wbinvd_on_cpus);
+
 int wbinvd_on_all_cpus(void)
 {
 	return on_each_cpu(__wbinvd, NULL, 1);
-- 
1.7.3.1.50.g1e633

[PATCH 2/2] kvm: Use wbinvd library functions

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

Replace local wbinvd helpers with equivalent x86 library functions.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/kvm/x86.c |   14 +++-----------
 1 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cdac9e5..8063ac0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -50,6 +50,7 @@
 
 #include <asm/debugreg.h>
 #include <asm/msr.h>
+#include <asm/smp.h>
 #include <asm/desc.h>
 #include <asm/mtrr.h>
 #include <asm/mce.h>
@@ -2029,11 +2030,6 @@ out:
 	return r;
 }
 
-static void wbinvd_ipi(void *garbage)
-{
-	wbinvd();
-}
-
 static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu)
 {
 	return vcpu->kvm->arch.iommu_domain &&
@@ -2047,8 +2043,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		if (kvm_x86_ops->has_wbinvd_exit())
 			cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask);
 		else if (vcpu->cpu != -1 && vcpu->cpu != cpu)
-			smp_call_function_single(vcpu->cpu,
-					wbinvd_ipi, NULL, 1);
+			wbinvd_on_cpu(vcpu->cpu);
 	}
 
 	kvm_x86_ops->vcpu_load(vcpu, cpu);
@@ -3978,10 +3973,7 @@ int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu)
 		return X86EMUL_CONTINUE;
 
 	if (kvm_x86_ops->has_wbinvd_exit()) {
-		preempt_disable();
-		smp_call_function_many(vcpu->arch.wbinvd_dirty_mask,
-				wbinvd_ipi, NULL, 1);
-		preempt_enable();
+		wbinvd_on_cpus(vcpu->arch.wbinvd_dirty_mask);
 		cpumask_clear(vcpu->arch.wbinvd_dirty_mask);
 	}
 	wbinvd();
-- 
1.7.3.1.50.g1e633

Re: [PATCH 1/2] x86, lib: Add a wbinvd helper for an arbitrary cpu set

[H. Peter Anvin]

On 11/24/2010 09:44 AM, Borislav Petkov wrote:
> From: Borislav Petkov <borislav.petkov@amd.com>
> 
> Add a wbinvd helper for an arbitrary set of CPUs.
> 

Are there any expected users of this other than KVM?

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

Re: [PATCH 1/2] x86, lib: Add a wbinvd helper for an arbitrary cpu set

[Borislav Petkov]

On Wed, Nov 24, 2010 at 12:49:06PM -0500, H. Peter Anvin wrote:
> On 11/24/2010 09:44 AM, Borislav Petkov wrote:
> > From: Borislav Petkov <borislav.petkov@amd.com>
> > 
> > Add a wbinvd helper for an arbitrary set of CPUs.
> > 
> 
> Are there any expected users of this other than KVM?

Not that I know of. I had an earlier version for kvm which did

for_each_cpu(cpu, mask)
	wbinvd_on_cpu(cpu)


but decided to add wbinvd_on_cpus() for completeness. Let me know what
your preference is.

Thanks.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
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