KVM: PPC: Book3S PR: Keep volatile reg values in vcpu rather than shadow_vcpu
Currently PR-style KVM keeps the volatile guest register values
(R0 - R13, CR, LR, CTR, XER, PC) in a shadow_vcpu struct rather than
the main kvm_vcpu struct. For 64-bit, the shadow_vcpu exists in two
places, a kmalloc'd struct and in the PACA, and it gets copied back
and forth in kvmppc_core_vcpu_load/put(), because the real-mode code
can't rely on being able to access the kmalloc'd struct.
This changes the code to copy the volatile values into the shadow_vcpu
as one of the last things done before entering the guest. Similarly
the values are copied back out of the shadow_vcpu to the kvm_vcpu
immediately after exiting the guest. We arrange for interrupts to be
still disabled at this point so that we can't get preempted on 64-bit
and end up copying values from the wrong PACA.
This means that the accessor functions in kvm_book3s.h for these
registers are greatly simplified, and are same between PR and HV KVM.
In places where accesses to shadow_vcpu fields are now replaced by
accesses to the kvm_vcpu, we can also remove the svcpu_get/put pairs.
Finally, on 64-bit, we don't need the kmalloc'd struct at all any more.
With this, the time to read the PVR one million times in a loop went
from 567.7ms to 575.5ms (averages of 6 values), an increase of about
1.4% for this worse-case test for guest entries and exits. The
standard deviation of the measurements is about 11ms, so the
difference is only marginally significant statistically.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 8d45f18..228a9ba 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -61,8 +61,6 @@
#ifdef CONFIG_PPC_BOOK3S_64
struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
memcpy(svcpu->slb, to_book3s(vcpu)->slb_shadow, sizeof(svcpu->slb));
- memcpy(&get_paca()->shadow_vcpu, to_book3s(vcpu)->shadow_vcpu,
- sizeof(get_paca()->shadow_vcpu));
svcpu->slb_max = to_book3s(vcpu)->slb_shadow_max;
svcpu_put(svcpu);
#endif
@@ -77,8 +75,6 @@
#ifdef CONFIG_PPC_BOOK3S_64
struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
memcpy(to_book3s(vcpu)->slb_shadow, svcpu->slb, sizeof(svcpu->slb));
- memcpy(to_book3s(vcpu)->shadow_vcpu, &get_paca()->shadow_vcpu,
- sizeof(get_paca()->shadow_vcpu));
to_book3s(vcpu)->slb_shadow_max = svcpu->slb_max;
svcpu_put(svcpu);
#endif
@@ -87,6 +83,60 @@
vcpu->cpu = -1;
}
+/* Copy data needed by real-mode code from vcpu to shadow vcpu */
+void kvmppc_copy_to_svcpu(struct kvmppc_book3s_shadow_vcpu *svcpu,
+ struct kvm_vcpu *vcpu)
+{
+ svcpu->gpr[0] = vcpu->arch.gpr[0];
+ svcpu->gpr[1] = vcpu->arch.gpr[1];
+ svcpu->gpr[2] = vcpu->arch.gpr[2];
+ svcpu->gpr[3] = vcpu->arch.gpr[3];
+ svcpu->gpr[4] = vcpu->arch.gpr[4];
+ svcpu->gpr[5] = vcpu->arch.gpr[5];
+ svcpu->gpr[6] = vcpu->arch.gpr[6];
+ svcpu->gpr[7] = vcpu->arch.gpr[7];
+ svcpu->gpr[8] = vcpu->arch.gpr[8];
+ svcpu->gpr[9] = vcpu->arch.gpr[9];
+ svcpu->gpr[10] = vcpu->arch.gpr[10];
+ svcpu->gpr[11] = vcpu->arch.gpr[11];
+ svcpu->gpr[12] = vcpu->arch.gpr[12];
+ svcpu->gpr[13] = vcpu->arch.gpr[13];
+ svcpu->cr = vcpu->arch.cr;
+ svcpu->xer = vcpu->arch.xer;
+ svcpu->ctr = vcpu->arch.ctr;
+ svcpu->lr = vcpu->arch.lr;
+ svcpu->pc = vcpu->arch.pc;
+}
+
+/* Copy data touched by real-mode code from shadow vcpu back to vcpu */
+void kvmppc_copy_from_svcpu(struct kvm_vcpu *vcpu,
+ struct kvmppc_book3s_shadow_vcpu *svcpu)
+{
+ vcpu->arch.gpr[0] = svcpu->gpr[0];
+ vcpu->arch.gpr[1] = svcpu->gpr[1];
+ vcpu->arch.gpr[2] = svcpu->gpr[2];
+ vcpu->arch.gpr[3] = svcpu->gpr[3];
+ vcpu->arch.gpr[4] = svcpu->gpr[4];
+ vcpu->arch.gpr[5] = svcpu->gpr[5];
+ vcpu->arch.gpr[6] = svcpu->gpr[6];
+ vcpu->arch.gpr[7] = svcpu->gpr[7];
+ vcpu->arch.gpr[8] = svcpu->gpr[8];
+ vcpu->arch.gpr[9] = svcpu->gpr[9];
+ vcpu->arch.gpr[10] = svcpu->gpr[10];
+ vcpu->arch.gpr[11] = svcpu->gpr[11];
+ vcpu->arch.gpr[12] = svcpu->gpr[12];
+ vcpu->arch.gpr[13] = svcpu->gpr[13];
+ vcpu->arch.cr = svcpu->cr;
+ vcpu->arch.xer = svcpu->xer;
+ vcpu->arch.ctr = svcpu->ctr;
+ vcpu->arch.lr = svcpu->lr;
+ vcpu->arch.pc = svcpu->pc;
+ vcpu->arch.shadow_srr1 = svcpu->shadow_srr1;
+ vcpu->arch.fault_dar = svcpu->fault_dar;
+ vcpu->arch.fault_dsisr = svcpu->fault_dsisr;
+ vcpu->arch.last_inst = svcpu->last_inst;
+}
+
int kvmppc_core_check_requests(struct kvm_vcpu *vcpu)
{
int r = 1; /* Indicate we want to get back into the guest */
@@ -388,22 +438,18 @@
if (page_found == -ENOENT) {
/* Page not found in guest PTE entries */
- struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
vcpu->arch.shared->dar = kvmppc_get_fault_dar(vcpu);
- vcpu->arch.shared->dsisr = svcpu->fault_dsisr;
+ vcpu->arch.shared->dsisr = vcpu->arch.fault_dsisr;
vcpu->arch.shared->msr |=
- (svcpu->shadow_srr1 & 0x00000000f8000000ULL);
- svcpu_put(svcpu);
+ vcpu->arch.shadow_srr1 & 0x00000000f8000000ULL;
kvmppc_book3s_queue_irqprio(vcpu, vec);
} else if (page_found == -EPERM) {
/* Storage protection */
- struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
vcpu->arch.shared->dar = kvmppc_get_fault_dar(vcpu);
- vcpu->arch.shared->dsisr = svcpu->fault_dsisr & ~DSISR_NOHPTE;
+ vcpu->arch.shared->dsisr = vcpu->arch.fault_dsisr & ~DSISR_NOHPTE;
vcpu->arch.shared->dsisr |= DSISR_PROTFAULT;
vcpu->arch.shared->msr |=
- svcpu->shadow_srr1 & 0x00000000f8000000ULL;
- svcpu_put(svcpu);
+ vcpu->arch.shadow_srr1 & 0x00000000f8000000ULL;
kvmppc_book3s_queue_irqprio(vcpu, vec);
} else if (page_found == -EINVAL) {
/* Page not found in guest SLB */
@@ -645,21 +691,26 @@
switch (exit_nr) {
case BOOK3S_INTERRUPT_INST_STORAGE:
{
- struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
- ulong shadow_srr1 = svcpu->shadow_srr1;
+ ulong shadow_srr1 = vcpu->arch.shadow_srr1;
vcpu->stat.pf_instruc++;
#ifdef CONFIG_PPC_BOOK3S_32
/* We set segments as unused segments when invalidating them. So
* treat the respective fault as segment fault. */
- if (svcpu->sr[kvmppc_get_pc(vcpu) >> SID_SHIFT] == SR_INVALID) {
- kvmppc_mmu_map_segment(vcpu, kvmppc_get_pc(vcpu));
- r = RESUME_GUEST;
+ {
+ struct kvmppc_book3s_shadow_vcpu *svcpu;
+ u32 sr;
+
+ svcpu = svcpu_get(vcpu);
+ sr = svcpu->sr[kvmppc_get_pc(vcpu) >> SID_SHIFT];
svcpu_put(svcpu);
- break;
+ if (sr == SR_INVALID) {
+ kvmppc_mmu_map_segment(vcpu, kvmppc_get_pc(vcpu));
+ r = RESUME_GUEST;
+ break;
+ }
}
#endif
- svcpu_put(svcpu);
/* only care about PTEG not found errors, but leave NX alone */
if (shadow_srr1 & 0x40000000) {
@@ -684,21 +735,26 @@
case BOOK3S_INTERRUPT_DATA_STORAGE:
{
ulong dar = kvmppc_get_fault_dar(vcpu);
- struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
- u32 fault_dsisr = svcpu->fault_dsisr;
+ u32 fault_dsisr = vcpu->arch.fault_dsisr;
vcpu->stat.pf_storage++;
#ifdef CONFIG_PPC_BOOK3S_32
/* We set segments as unused segments when invalidating them. So
* treat the respective fault as segment fault. */
- if ((svcpu->sr[dar >> SID_SHIFT]) == SR_INVALID) {
- kvmppc_mmu_map_segment(vcpu, dar);
- r = RESUME_GUEST;
+ {
+ struct kvmppc_book3s_shadow_vcpu *svcpu;
+ u32 sr;
+
+ svcpu = svcpu_get(vcpu);
+ sr = svcpu->sr[dar >> SID_SHIFT];
svcpu_put(svcpu);
- break;
+ if (sr == SR_INVALID) {
+ kvmppc_mmu_map_segment(vcpu, dar);
+ r = RESUME_GUEST;
+ break;
+ }
}
#endif
- svcpu_put(svcpu);
/* The only case we need to handle is missing shadow PTEs */
if (fault_dsisr & DSISR_NOHPTE) {
@@ -745,13 +801,10 @@
case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
{
enum emulation_result er;
- struct kvmppc_book3s_shadow_vcpu *svcpu;
ulong flags;
program_interrupt:
- svcpu = svcpu_get(vcpu);
- flags = svcpu->shadow_srr1 & 0x1f0000ull;
- svcpu_put(svcpu);
+ flags = vcpu->arch.shadow_srr1 & 0x1f0000ull;
if (vcpu->arch.shared->msr & MSR_PR) {
#ifdef EXIT_DEBUG
@@ -883,9 +936,7 @@
break;
default:
{
- struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
- ulong shadow_srr1 = svcpu->shadow_srr1;
- svcpu_put(svcpu);
+ ulong shadow_srr1 = vcpu->arch.shadow_srr1;
/* Ugh - bork here! What did we get? */
printk(KERN_EMERG "exit_nr=0x%x | pc=0x%lx | msr=0x%lx\n",
exit_nr, kvmppc_get_pc(vcpu), shadow_srr1);
@@ -1060,11 +1111,12 @@
if (!vcpu_book3s)
goto out;
+#ifdef CONFIG_KVM_BOOK3S_32
vcpu_book3s->shadow_vcpu =
kzalloc(sizeof(*vcpu_book3s->shadow_vcpu), GFP_KERNEL);
if (!vcpu_book3s->shadow_vcpu)
goto free_vcpu;
-
+#endif
vcpu = &vcpu_book3s->vcpu;
err = kvm_vcpu_init(vcpu, kvm, id);
if (err)
@@ -1098,8 +1150,10 @@
uninit_vcpu:
kvm_vcpu_uninit(vcpu);
free_shadow_vcpu:
+#ifdef CONFIG_KVM_BOOK3S_32
kfree(vcpu_book3s->shadow_vcpu);
free_vcpu:
+#endif
vfree(vcpu_book3s);
out:
return ERR_PTR(err);