KVM: PPC: Disable MSR_FEx for Cell hosts

agraf · avikivity · commit 05b0ab1c0bb5 · 2010-05-17T12:17:21.000+03:00
Cell can't handle MSR_FE0 and MSR_FE1 too well. It gets dog slow. So let's just override the guest whenever we see one of the two and mask them out. See commit ddf5f75 for reference. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
@@ -357,6 +357,10 @@ void kvmppc_set_pvr(struct kvm_vcpu *vcpu, u32 pvr)
 	    !strcmp(cur_cpu_spec->platform, "ppc970"))
 		vcpu->arch.hflags |= BOOK3S_HFLAG_DCBZ32;
 
+	/* Cell performs badly if MSR_FEx are set. So let's hope nobody
+	   really needs them in a VM on Cell and force disable them. */
+	if (!strcmp(cur_cpu_spec->platform, "ppc-cell-be"))
+		to_book3s(vcpu)->msr_mask &= ~(MSR_FE0 | MSR_FE1);
 }
 
 /* Book3s_32 CPUs always have 32 bytes cache line size, which Linux assumes. To

Original file line number	Diff line number	Diff line change
`@@ -357,6 +357,10 @@ void kvmppc_set_pvr(struct kvm_vcpu *vcpu, u32 pvr)`
`357`	`357`	`!strcmp(cur_cpu_spec->platform, "ppc970"))`
`358`	`358`	`vcpu->arch.hflags \|= BOOK3S_HFLAG_DCBZ32;`
`359`	`359`
	`360`	`+ /* Cell performs badly if MSR_FEx are set. So let's hope nobody`
	`361`	`+ really needs them in a VM on Cell and force disable them. */`
	`362`	`+ if (!strcmp(cur_cpu_spec->platform, "ppc-cell-be"))`
	`363`	`+ to_book3s(vcpu)->msr_mask &= ~(MSR_FE0 \| MSR_FE1);`
`360`	`364`	`}`
`361`	`365`
`362`	`366`	`/* Book3s_32 CPUs always have 32 bytes cache line size, which Linux assumes. To`