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Commit 0acb9111 authored by Paul Mackerras's avatar Paul Mackerras Committed by Benjamin Herrenschmidt
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powerpc/kvm/book3s_hv: Preserve guest CFAR register value 



The CFAR (Come-From Address Register) is a useful debugging aid that
exists on POWER7 processors.  Currently HV KVM doesn't save or restore
the CFAR register for guest vcpus, making the CFAR of limited use in
guests.

This adds the necessary code to capture the CFAR value saved in the
early exception entry code (it has to be saved before any branch is
executed), save it in the vcpu.arch struct, and restore it on entry
to the guest.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 1707dd16

arch/powerpc/include/asm/exception-64s.h

+6 −2
Original line number Diff line number Diff line
@@ -199,6 +199,10 @@ END_FTR_SECTION_NESTED(ftr,ftr,943) 


#define __KVM_HANDLER(area, h, n)					\

do_kvm_##n:								\

	BEGIN_FTR_SECTION_NESTED(947)					\

	ld	r10,area+EX_CFAR(r13);					\

	std	r10,HSTATE_CFAR(r13);					\

	END_FTR_SECTION_NESTED(CPU_FTR_CFAR,CPU_FTR_CFAR,947);		\

	ld	r10,area+EX_R10(r13);					\

	stw	r9,HSTATE_SCRATCH1(r13);				\

	ld	r9,area+EX_R9(r13);					\

arch/powerpc/include/asm/kvm_book3s_asm.h

+3 −0
Original line number Diff line number Diff line
@@ -93,6 +93,9 @@ struct kvmppc_host_state { 
	u64 host_dscr;

	u64 dec_expires;

#endif

#ifdef CONFIG_PPC_BOOK3S_64

	u64 cfar;

#endif

};



struct kvmppc_book3s_shadow_vcpu {

arch/powerpc/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -440,6 +440,7 @@ struct kvm_vcpu_arch { 
	ulong uamor;

	u32 ctrl;

	ulong dabr;

	ulong cfar;

#endif

	u32 vrsave; /* also USPRG0 */

	u32 mmucr;

arch/powerpc/kernel/asm-offsets.c

+5 −0
Original line number Diff line number Diff line
@@ -479,6 +479,7 @@ int main(void) 
	DEFINE(VCPU_LAST_INST, offsetof(struct kvm_vcpu, arch.last_inst));

	DEFINE(VCPU_TRAP, offsetof(struct kvm_vcpu, arch.trap));

	DEFINE(VCPU_PTID, offsetof(struct kvm_vcpu, arch.ptid));

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

	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));
@@ -558,6 +559,10 @@ int main(void) 
	DEFINE(IPI_PRIORITY, IPI_PRIORITY);

#endif /* CONFIG_KVM_BOOK3S_64_HV */



#ifdef CONFIG_PPC_BOOK3S_64

	HSTATE_FIELD(HSTATE_CFAR, cfar);

#endif /* CONFIG_PPC_BOOK3S_64 */



#else /* CONFIG_PPC_BOOK3S */

	DEFINE(VCPU_CR, offsetof(struct kvm_vcpu, arch.cr));

	DEFINE(VCPU_XER, offsetof(struct kvm_vcpu, arch.xer));

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+9 −0
Original line number Diff line number Diff line
@@ -539,6 +539,11 @@ fast_guest_return: 


	/* Enter guest */



BEGIN_FTR_SECTION

	ld	r5, VCPU_CFAR(r4)

	mtspr	SPRN_CFAR, r5

END_FTR_SECTION_IFSET(CPU_FTR_CFAR)



	ld	r5, VCPU_LR(r4)

	lwz	r6, VCPU_CR(r4)

	mtlr	r5
@@ -604,6 +609,10 @@ kvmppc_interrupt: 
	lwz	r4, HSTATE_SCRATCH1(r13)

	std	r3, VCPU_GPR(R12)(r9)

	stw	r4, VCPU_CR(r9)

BEGIN_FTR_SECTION

	ld	r3, HSTATE_CFAR(r13)

	std	r3, VCPU_CFAR(r9)

END_FTR_SECTION_IFSET(CPU_FTR_CFAR)



	/* Restore R1/R2 so we can handle faults */

	ld	r1, HSTATE_HOST_R1(r13)