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>

1 files changed, 35 insertions, 185 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 14a4741..40f22d9 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -200,140 +200,76 @@ extern void kvm_return_point(void);
 #include <asm/kvm_book3s_64.h>
 #endif
 
-#ifdef CONFIG_KVM_BOOK3S_PR
-
-static inline unsigned long kvmppc_interrupt_offset(struct kvm_vcpu *vcpu)
-{
-	return to_book3s(vcpu)->hior;
-}
-
-static inline void kvmppc_update_int_pending(struct kvm_vcpu *vcpu,
-			unsigned long pending_now, unsigned long old_pending)
-{
-	if (pending_now)
-		vcpu->arch.shared->int_pending = 1;
-	else if (old_pending)
-		vcpu->arch.shared->int_pending = 0;
-}
-
 static inline void kvmppc_set_gpr(struct kvm_vcpu *vcpu, int num, ulong val)
 {
-	if ( num < 14 ) {
-		struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-		svcpu->gpr[num] = val;
-		svcpu_put(svcpu);
-		to_book3s(vcpu)->shadow_vcpu->gpr[num] = val;
-	} else
-		vcpu->arch.gpr[num] = val;
+	vcpu->arch.gpr[num] = val;
 }
 
 static inline ulong kvmppc_get_gpr(struct kvm_vcpu *vcpu, int num)
 {
-	if ( num < 14 ) {
-		struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-		ulong r = svcpu->gpr[num];
-		svcpu_put(svcpu);
-		return r;
-	} else
-		return vcpu->arch.gpr[num];
+	return vcpu->arch.gpr[num];
 }
 
 static inline void kvmppc_set_cr(struct kvm_vcpu *vcpu, u32 val)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	svcpu->cr = val;
-	svcpu_put(svcpu);
-	to_book3s(vcpu)->shadow_vcpu->cr = val;
+	vcpu->arch.cr = val;
 }
 
 static inline u32 kvmppc_get_cr(struct kvm_vcpu *vcpu)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	u32 r;
-	r = svcpu->cr;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.cr;
 }
 
 static inline void kvmppc_set_xer(struct kvm_vcpu *vcpu, u32 val)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	svcpu->xer = val;
-	to_book3s(vcpu)->shadow_vcpu->xer = val;
-	svcpu_put(svcpu);
+	vcpu->arch.xer = val;
 }
 
 static inline u32 kvmppc_get_xer(struct kvm_vcpu *vcpu)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	u32 r;
-	r = svcpu->xer;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.xer;
 }
 
 static inline void kvmppc_set_ctr(struct kvm_vcpu *vcpu, ulong val)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	svcpu->ctr = val;
-	svcpu_put(svcpu);
+	vcpu->arch.ctr = val;
 }
 
 static inline ulong kvmppc_get_ctr(struct kvm_vcpu *vcpu)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	ulong r;
-	r = svcpu->ctr;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.ctr;
 }
 
 static inline void kvmppc_set_lr(struct kvm_vcpu *vcpu, ulong val)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	svcpu->lr = val;
-	svcpu_put(svcpu);
+	vcpu->arch.lr = val;
 }
 
 static inline ulong kvmppc_get_lr(struct kvm_vcpu *vcpu)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	ulong r;
-	r = svcpu->lr;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.lr;
 }
 
 static inline void kvmppc_set_pc(struct kvm_vcpu *vcpu, ulong val)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	svcpu->pc = val;
-	svcpu_put(svcpu);
+	vcpu->arch.pc = val;
 }
 
 static inline ulong kvmppc_get_pc(struct kvm_vcpu *vcpu)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	ulong r;
-	r = svcpu->pc;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.pc;
 }
 
 static inline u32 kvmppc_get_last_inst(struct kvm_vcpu *vcpu)
 {
 	ulong pc = kvmppc_get_pc(vcpu);
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	u32 r;
 
 	/* Load the instruction manually if it failed to do so in the
 	 * exit path */
-	if (svcpu->last_inst == KVM_INST_FETCH_FAILED)
-		kvmppc_ld(vcpu, &pc, sizeof(u32), &svcpu->last_inst, false);
+	if (vcpu->arch.last_inst == KVM_INST_FETCH_FAILED)
+		kvmppc_ld(vcpu, &pc, sizeof(u32), &vcpu->arch.last_inst, false);
 
-	r = svcpu->last_inst;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.last_inst;
 }
 
 /*
@@ -344,26 +280,34 @@ static inline u32 kvmppc_get_last_inst(struct kvm_vcpu *vcpu)
 static inline u32 kvmppc_get_last_sc(struct kvm_vcpu *vcpu)
 {
 	ulong pc = kvmppc_get_pc(vcpu) - 4;
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	u32 r;
 
 	/* Load the instruction manually if it failed to do so in the
 	 * exit path */
-	if (svcpu->last_inst == KVM_INST_FETCH_FAILED)
-		kvmppc_ld(vcpu, &pc, sizeof(u32), &svcpu->last_inst, false);
+	if (vcpu->arch.last_inst == KVM_INST_FETCH_FAILED)
+		kvmppc_ld(vcpu, &pc, sizeof(u32), &vcpu->arch.last_inst, false);
 
-	r = svcpu->last_inst;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.last_inst;
 }
 
 static inline ulong kvmppc_get_fault_dar(struct kvm_vcpu *vcpu)
 {
-	struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
-	ulong r;
-	r = svcpu->fault_dar;
-	svcpu_put(svcpu);
-	return r;
+	return vcpu->arch.fault_dar;
+}
+
+#ifdef CONFIG_KVM_BOOK3S_PR
+
+static inline unsigned long kvmppc_interrupt_offset(struct kvm_vcpu *vcpu)
+{
+	return to_book3s(vcpu)->hior;
+}
+
+static inline void kvmppc_update_int_pending(struct kvm_vcpu *vcpu,
+			unsigned long pending_now, unsigned long old_pending)
+{
+	if (pending_now)
+		vcpu->arch.shared->int_pending = 1;
+	else if (old_pending)
+		vcpu->arch.shared->int_pending = 0;
 }
 
 static inline bool kvmppc_critical_section(struct kvm_vcpu *vcpu)
@@ -397,100 +341,6 @@ static inline void kvmppc_update_int_pending(struct kvm_vcpu *vcpu,
 {
 }
 
-static inline void kvmppc_set_gpr(struct kvm_vcpu *vcpu, int num, ulong val)
-{
-	vcpu->arch.gpr[num] = val;
-}
-
-static inline ulong kvmppc_get_gpr(struct kvm_vcpu *vcpu, int num)
-{
-	return vcpu->arch.gpr[num];
-}
-
-static inline void kvmppc_set_cr(struct kvm_vcpu *vcpu, u32 val)
-{
-	vcpu->arch.cr = val;
-}
-
-static inline u32 kvmppc_get_cr(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.cr;
-}
-
-static inline void kvmppc_set_xer(struct kvm_vcpu *vcpu, u32 val)
-{
-	vcpu->arch.xer = val;
-}
-
-static inline u32 kvmppc_get_xer(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.xer;
-}
-
-static inline void kvmppc_set_ctr(struct kvm_vcpu *vcpu, ulong val)
-{
-	vcpu->arch.ctr = val;
-}
-
-static inline ulong kvmppc_get_ctr(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.ctr;
-}
-
-static inline void kvmppc_set_lr(struct kvm_vcpu *vcpu, ulong val)
-{
-	vcpu->arch.lr = val;
-}
-
-static inline ulong kvmppc_get_lr(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.lr;
-}
-
-static inline void kvmppc_set_pc(struct kvm_vcpu *vcpu, ulong val)
-{
-	vcpu->arch.pc = val;
-}
-
-static inline ulong kvmppc_get_pc(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.pc;
-}
-
-static inline u32 kvmppc_get_last_inst(struct kvm_vcpu *vcpu)
-{
-	ulong pc = kvmppc_get_pc(vcpu);
-
-	/* Load the instruction manually if it failed to do so in the
-	 * exit path */
-	if (vcpu->arch.last_inst == KVM_INST_FETCH_FAILED)
-		kvmppc_ld(vcpu, &pc, sizeof(u32), &vcpu->arch.last_inst, false);
-
-	return vcpu->arch.last_inst;
-}
-
-/*
- * Like kvmppc_get_last_inst(), but for fetching a sc instruction.
- * Because the sc instruction sets SRR0 to point to the following
- * instruction, we have to fetch from pc - 4.
- */
-static inline u32 kvmppc_get_last_sc(struct kvm_vcpu *vcpu)
-{
-	ulong pc = kvmppc_get_pc(vcpu) - 4;
-
-	/* Load the instruction manually if it failed to do so in the
-	 * exit path */
-	if (vcpu->arch.last_inst == KVM_INST_FETCH_FAILED)
-		kvmppc_ld(vcpu, &pc, sizeof(u32), &vcpu->arch.last_inst, false);
-
-	return vcpu->arch.last_inst;
-}
-
-static inline ulong kvmppc_get_fault_dar(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.fault_dar;
-}
-
 static inline bool kvmppc_critical_section(struct kvm_vcpu *vcpu)
 {
 	return false;