From 4a157d61b48c7cdb8d751001442a14ebac80229f Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Wed, 3 Dec 2014 13:30:39 +1100 Subject: [PATCH] KVM: PPC: Book3S HV: Fix endianness of instruction obtained from HEIR register There are two ways in which a guest instruction can be obtained from the guest in the guest exit code in book3s_hv_rmhandlers.S. If the exit was caused by a Hypervisor Emulation interrupt (i.e. an illegal instruction), the offending instruction is in the HEIR register (Hypervisor Emulation Instruction Register). If the exit was caused by a load or store to an emulated MMIO device, we load the instruction from the guest by turning data relocation on and loading the instruction with an lwz instruction. Unfortunately, in the case where the guest has opposite endianness to the host, these two methods give results of different endianness, but both get put into vcpu->arch.last_inst. The HEIR value has been loaded using guest endianness, whereas the lwz will load the instruction using host endianness. The rest of the code that uses vcpu->arch.last_inst assumes it was loaded using host endianness. To fix this, we define a new vcpu field to store the HEIR value. Then, in kvmppc_handle_exit_hv(), we transfer the value from this new field to vcpu->arch.last_inst, doing a byte-swap if the guest and host endianness differ. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/include/asm/kvm_host.h | 2 ++ arch/powerpc/kernel/asm-offsets.c | 1 + arch/powerpc/kvm/book3s_hv.c | 4 ++++ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 4 ++-- 4 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 5686a429d4b7..65441875b025 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -651,6 +651,8 @@ struct kvm_vcpu_arch { spinlock_t tbacct_lock; u64 busy_stolen; u64 busy_preempt; + + u32 emul_inst; #endif }; diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 815212e9d7ba..b14716bbb7b5 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -498,6 +498,7 @@ int main(void) DEFINE(VCPU_DAR, offsetof(struct kvm_vcpu, arch.shregs.dar)); DEFINE(VCPU_VPA, offsetof(struct kvm_vcpu, arch.vpa.pinned_addr)); DEFINE(VCPU_VPA_DIRTY, offsetof(struct kvm_vcpu, arch.vpa.dirty)); + DEFINE(VCPU_HEIR, offsetof(struct kvm_vcpu, arch.emul_inst)); #endif #ifdef CONFIG_PPC_BOOK3S DEFINE(VCPU_VCPUID, offsetof(struct kvm_vcpu, vcpu_id)); diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 1ee4e9e786cc..299351e77eb9 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -831,6 +831,10 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, * Accordingly return to Guest or Host. */ case BOOK3S_INTERRUPT_H_EMUL_ASSIST: + if (vcpu->arch.emul_inst != KVM_INST_FETCH_FAILED) + vcpu->arch.last_inst = kvmppc_need_byteswap(vcpu) ? + swab32(vcpu->arch.emul_inst) : + vcpu->arch.emul_inst; if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) { r = kvmppc_emulate_debug_inst(run, vcpu); } else { diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index c0f9e68c5db2..26a5b8d4dd3c 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -983,13 +983,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) stw r12,VCPU_TRAP(r9) - /* Save HEIR (HV emulation assist reg) in last_inst + /* Save HEIR (HV emulation assist reg) in emul_inst if this is an HEI (HV emulation interrupt, e40) */ li r3,KVM_INST_FETCH_FAILED cmpwi r12,BOOK3S_INTERRUPT_H_EMUL_ASSIST bne 11f mfspr r3,SPRN_HEIR -11: stw r3,VCPU_LAST_INST(r9) +11: stw r3,VCPU_HEIR(r9) /* these are volatile across C function calls */ mfctr r3 -- 2.20.1