Patchwork kvm/powerpc/e500mc: fix tlb invalidation on cpu migration

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Submitter Scott Wood
Date Feb. 19, 2013, 4:13 a.m.
Message ID <20130219041309.GA17075@home.buserror.net>
Download mbox | patch
Permalink /patch/221613/
State New
Headers show

Comments

Scott Wood - Feb. 19, 2013, 4:13 a.m.
The existing check handles the case where we've migrated to a different
core than we last ran on, but it doesn't handle the case where we're
still on the same cpu we last ran on, but some other vcpu has run on
this cpu in the meantime.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
This seems to have been the cause of the userspace segfaults I was
seeing (the other TLB patches I posted are still needed as well).

 arch/powerpc/kvm/e500mc.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
Alexander Graf - March 8, 2013, 12:11 p.m.
On 19.02.2013, at 05:13, Scott Wood wrote:

> The existing check handles the case where we've migrated to a different
> core than we last ran on, but it doesn't handle the case where we're
> still on the same cpu we last ran on, but some other vcpu has run on
> this cpu in the meantime.
> 
> Signed-off-by: Scott Wood <scottwood@freescale.com>
> ---
> This seems to have been the cause of the userspace segfaults I was
> seeing (the other TLB patches I posted are still needed as well).
> 
> arch/powerpc/kvm/e500mc.c |    6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
> index 1f89d26..8637689 100644
> --- a/arch/powerpc/kvm/e500mc.c
> +++ b/arch/powerpc/kvm/e500mc.c
> @@ -111,6 +111,7 @@ void kvmppc_mmu_msr_notify(struct kvm_vcpu *vcpu, u32 old_msr)
> void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> {
> 	struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
> +	static struct kvm_vcpu *last_vcpu_on_cpu[NR_CPUS];

Why not use DEFINE_PER_CPU?


Alex

> 
> 	kvmppc_booke_vcpu_load(vcpu, cpu);
> 
> @@ -136,8 +137,11 @@ void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> 	mtspr(SPRN_GDEAR, vcpu->arch.shared->dar);
> 	mtspr(SPRN_GESR, vcpu->arch.shared->esr);
> 
> -	if (vcpu->arch.oldpir != mfspr(SPRN_PIR))
> +	if (vcpu->arch.oldpir != mfspr(SPRN_PIR) ||
> +	    last_vcpu_on_cpu[smp_processor_id()] != vcpu) {
> 		kvmppc_e500_tlbil_all(vcpu_e500);
> +		last_vcpu_on_cpu[smp_processor_id()] = vcpu;
> +	}
> 
> 	kvmppc_load_guest_fp(vcpu);
> }
> -- 
> 1.7.9.5
> 

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Patch

diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
index 1f89d26..8637689 100644
--- a/arch/powerpc/kvm/e500mc.c
+++ b/arch/powerpc/kvm/e500mc.c
@@ -111,6 +111,7 @@  void kvmppc_mmu_msr_notify(struct kvm_vcpu *vcpu, u32 old_msr)
 void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
+	static struct kvm_vcpu *last_vcpu_on_cpu[NR_CPUS];
 
 	kvmppc_booke_vcpu_load(vcpu, cpu);
 
@@ -136,8 +137,11 @@  void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	mtspr(SPRN_GDEAR, vcpu->arch.shared->dar);
 	mtspr(SPRN_GESR, vcpu->arch.shared->esr);
 
-	if (vcpu->arch.oldpir != mfspr(SPRN_PIR))
+	if (vcpu->arch.oldpir != mfspr(SPRN_PIR) ||
+	    last_vcpu_on_cpu[smp_processor_id()] != vcpu) {
 		kvmppc_e500_tlbil_all(vcpu_e500);
+		last_vcpu_on_cpu[smp_processor_id()] = vcpu;
+	}
 
 	kvmppc_load_guest_fp(vcpu);
 }