KVM: ppc: Write only modified shadow entries into the TLB on exit
Track which TLB entries need to be written, instead of overwriting everything
below the high water mark. Typically only a single guest TLB entry will be
modified in a single exit.
Guest boot time performance improvement: about 15%.
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index b756071..90a6fc4 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -27,6 +27,7 @@
#include <asm/cputable.h>
#include <asm/uaccess.h>
#include <asm/kvm_ppc.h>
+#include <asm/tlbflush.h>
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
@@ -307,14 +308,28 @@
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
+ int i;
+
if (vcpu->guest_debug.enabled)
kvmppc_load_guest_debug_registers(vcpu);
+
+ /* Mark every guest entry in the shadow TLB entry modified, so that they
+ * will all be reloaded on the next vcpu run (instead of being
+ * demand-faulted). */
+ for (i = 0; i <= tlb_44x_hwater; i++)
+ kvmppc_tlbe_set_modified(vcpu, i);
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
if (vcpu->guest_debug.enabled)
kvmppc_restore_host_debug_state(vcpu);
+
+ /* Don't leave guest TLB entries resident when being de-scheduled. */
+ /* XXX It would be nice to differentiate between heavyweight exit and
+ * sched_out here, since we could avoid the TLB flush for heavyweight
+ * exits. */
+ _tlbia();
}
int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,