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Commit a2d56020 authored by Paul Mackerras's avatar Paul Mackerras Committed by Alexander Graf
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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: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent f2481771

arch/powerpc/include/asm/kvm_book3s.h

+35 −185
Original line number Diff line number Diff line
@@ -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;

}



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];

}



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;

arch/powerpc/include/asm/kvm_book3s_asm.h

+3 −3
Original line number Diff line number Diff line
@@ -109,14 +109,14 @@ struct kvmppc_book3s_shadow_vcpu { 
	ulong gpr[14];

	u32 cr;

	u32 xer;



	u32 fault_dsisr;

	u32 last_inst;

	ulong ctr;

	ulong lr;

	ulong pc;



	ulong shadow_srr1;

	ulong fault_dar;

	u32 fault_dsisr;

	u32 last_inst;



#ifdef CONFIG_PPC_BOOK3S_32

	u32     sr[16];			/* Guest SRs */

arch/powerpc/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -463,6 +463,7 @@ struct kvm_vcpu_arch { 
	ulong dabr;

	ulong cfar;

	ulong ppr;

	ulong shadow_srr1;

#endif

	u32 vrsave; /* also USPRG0 */

	u32 mmucr;

arch/powerpc/kernel/asm-offsets.c

+2 −2
Original line number Diff line number Diff line
@@ -520,6 +520,7 @@ int main(void) 
	DEFINE(VCPU_PTID, offsetof(struct kvm_vcpu, arch.ptid));

	DEFINE(VCPU_CFAR, offsetof(struct kvm_vcpu, arch.cfar));

	DEFINE(VCPU_PPR, offsetof(struct kvm_vcpu, arch.ppr));

	DEFINE(VCPU_SHADOW_SRR1, offsetof(struct kvm_vcpu, arch.shadow_srr1));

	DEFINE(VCORE_ENTRY_EXIT, offsetof(struct kvmppc_vcore, entry_exit_count));

	DEFINE(VCORE_NAP_COUNT, offsetof(struct kvmppc_vcore, nap_count));

	DEFINE(VCORE_IN_GUEST, offsetof(struct kvmppc_vcore, in_guest));
@@ -527,14 +528,13 @@ int main(void) 
	DEFINE(VCORE_TB_OFFSET, offsetof(struct kvmppc_vcore, tb_offset));

	DEFINE(VCORE_LPCR, offsetof(struct kvmppc_vcore, lpcr));

	DEFINE(VCORE_PCR, offsetof(struct kvmppc_vcore, pcr));

	DEFINE(VCPU_SVCPU, offsetof(struct kvmppc_vcpu_book3s, shadow_vcpu) -

			   offsetof(struct kvmppc_vcpu_book3s, vcpu));

	DEFINE(VCPU_SLB_E, offsetof(struct kvmppc_slb, orige));

	DEFINE(VCPU_SLB_V, offsetof(struct kvmppc_slb, origv));

	DEFINE(VCPU_SLB_SIZE, sizeof(struct kvmppc_slb));



#ifdef CONFIG_PPC_BOOK3S_64

#ifdef CONFIG_KVM_BOOK3S_PR

	DEFINE(PACA_SVCPU, offsetof(struct paca_struct, shadow_vcpu));

# define SVCPU_FIELD(x, f)	DEFINE(x, offsetof(struct paca_struct, shadow_vcpu.f))

#else

# define SVCPU_FIELD(x, f)

arch/powerpc/kvm/book3s_emulate.c

+2 −6
Original line number Diff line number Diff line
@@ -267,12 +267,9 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu, 


			r = kvmppc_st(vcpu, &addr, 32, zeros, true);

			if ((r == -ENOENT) || (r == -EPERM)) {

				struct kvmppc_book3s_shadow_vcpu *svcpu;



				svcpu = svcpu_get(vcpu);

				*advance = 0;

				vcpu->arch.shared->dar = vaddr;

				svcpu->fault_dar = vaddr;

				vcpu->arch.fault_dar = vaddr;



				dsisr = DSISR_ISSTORE;

				if (r == -ENOENT)
@@ -281,8 +278,7 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu, 
					dsisr |= DSISR_PROTFAULT;



				vcpu->arch.shared->dsisr = dsisr;

				svcpu->fault_dsisr = dsisr;

				svcpu_put(svcpu);

				vcpu->arch.fault_dsisr = dsisr;



				kvmppc_book3s_queue_irqprio(vcpu,

					BOOK3S_INTERRUPT_DATA_STORAGE);