From 0acb91112a148fbb31678e66839ef757f3be3aa4 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Mon, 4 Feb 2013 18:10:51 +0000 Subject: [PATCH] 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: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/exception-64s.h | 8 ++++++-- arch/powerpc/include/asm/kvm_book3s_asm.h | 3 +++ arch/powerpc/include/asm/kvm_host.h | 1 + arch/powerpc/kernel/asm-offsets.c | 5 +++++ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 9 +++++++++ 5 files changed, 24 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 4dfc51588be5..05e6d2ee1db9 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -199,10 +199,14 @@ 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); \ + stw r9,HSTATE_SCRATCH1(r13); \ ld r9,area+EX_R9(r13); \ - std r12,HSTATE_SCRATCH0(r13); \ + std r12,HSTATE_SCRATCH0(r13); \ li r12,n; \ b kvmppc_interrupt diff --git a/arch/powerpc/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h index 88609b23b775..cdc3d2717cc6 100644 --- a/arch/powerpc/include/asm/kvm_book3s_asm.h +++ b/arch/powerpc/include/asm/kvm_book3s_asm.h @@ -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 { diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index ca9bf459db6a..03d7beae89a0 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -440,6 +440,7 @@ struct kvm_vcpu_arch { ulong uamor; u32 ctrl; ulong dabr; + ulong cfar; #endif u32 vrsave; /* also USPRG0 */ u32 mmucr; diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index beddba432518..e295a09b1f06 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -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)); diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 10b6c358dd77..e33d11f1b977 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -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) -- 2.20.1