[PATCH 2/3] KVM: PPC: Book3S HV: Save/restore SIAR and SDAR along with other PMU registers

[Paul Mackerras <paulus@samba.org>]

Currently we are not saving and restoring the SIAR and SDAR registers in
the PMU (performance monitor unit) on guest entry and exit.  The result
is that performance monitoring tools in the guest could get false
information about where a program was executing and what data it was
accessing at the time of a performance monitor interrupt.  This fixes
it by saving and restoring these registers along with the other PMU
registers on guest entry/exit.

This also provides a way for userspace to access these values for a
vcpu via the one_reg interface.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/include/asm/kvm_host.h     |  2 ++
 arch/powerpc/kernel/asm-offsets.c       |  2 ++
 arch/powerpc/kvm/book3s_hv.c            | 12 ++++++++++++
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 12 ++++++++++++
 4 files changed, 28 insertions(+)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 3328353..91b833d 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -498,6 +498,8 @@ struct kvm_vcpu_arch {
 
 	u64 mmcr[3];
 	u32 pmc[8];
+	u64 siar;
+	u64 sdar;
 
 #ifdef CONFIG_KVM_EXIT_TIMING
 	struct mutex exit_timing_lock;
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index a67c76e..822b6ba 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -506,6 +506,8 @@ int main(void)
 	DEFINE(VCPU_PRODDED, offsetof(struct kvm_vcpu, arch.prodded));
 	DEFINE(VCPU_MMCR, offsetof(struct kvm_vcpu, arch.mmcr));
 	DEFINE(VCPU_PMC, offsetof(struct kvm_vcpu, arch.pmc));
+	DEFINE(VCPU_SIAR, offsetof(struct kvm_vcpu, arch.siar));
+	DEFINE(VCPU_SDAR, offsetof(struct kvm_vcpu, arch.sdar));
 	DEFINE(VCPU_SLB, offsetof(struct kvm_vcpu, arch.slb));
 	DEFINE(VCPU_SLB_MAX, offsetof(struct kvm_vcpu, arch.slb_max));
 	DEFINE(VCPU_SLB_NR, offsetof(struct kvm_vcpu, arch.slb_nr));
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 2b95c45..9df824f 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -771,6 +771,12 @@ int kvmppc_get_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
 		}
 		break;
 #endif /* CONFIG_VSX */
+	case KVM_REG_PPC_SIAR:
+		*val = get_reg_val(id, vcpu->arch.siar);
+		break;
+	case KVM_REG_PPC_SDAR:
+		*val = get_reg_val(id, vcpu->arch.sdar);
+		break;
 	case KVM_REG_PPC_VPA_ADDR:
 		spin_lock(&vcpu->arch.vpa_update_lock);
 		*val = get_reg_val(id, vcpu->arch.vpa.next_gpa);
@@ -855,6 +861,12 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
 		}
 		break;
 #endif /* CONFIG_VSX */
+	case KVM_REG_PPC_SIAR:
+		vcpu->arch.siar = set_reg_val(id, *val);
+		break;
+	case KVM_REG_PPC_SDAR:
+		vcpu->arch.sdar = set_reg_val(id, *val);
+		break;
 	case KVM_REG_PPC_VPA_ADDR:
 		addr = set_reg_val(id, *val);
 		r = -EINVAL;
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 60dce5b..2e1dd6c 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -198,6 +198,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
 	ld	r6, VCPU_MMCR + 16(r4)
 	mtspr	SPRN_MMCR1, r5
 	mtspr	SPRN_MMCRA, r6
+BEGIN_FTR_SECTION
+	ld	r7, VCPU_SIAR(r4)
+	ld	r8, VCPU_SDAR(r4)
+	mtspr	SPRN_SIAR, r7
+	mtspr	SPRN_SDAR, r8
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 	mtspr	SPRN_MMCR0, r3
 	isync
 
@@ -1125,6 +1131,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 	std	r4, VCPU_MMCR(r9)
 	std	r5, VCPU_MMCR + 8(r9)
 	std	r6, VCPU_MMCR + 16(r9)
+BEGIN_FTR_SECTION
+	mfspr	r7, SPRN_SIAR
+	mfspr	r8, SPRN_SDAR
+	std	r7, VCPU_SIAR(r9)
+	std	r8, VCPU_SDAR(r9)
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
 	mfspr	r3, SPRN_PMC1
 	mfspr	r4, SPRN_PMC2
 	mfspr	r5, SPRN_PMC3
-- 
1.8.4.rc3