From 420ea09b645b0fb05b326a539190c41ee900ef50 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 6 Dec 2016 19:27:18 +0000 Subject: [PATCH] KVM: MIPS/T&E: Abstract bad access handling MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Abstract the handling of bad guest loads and stores which may need to trigger an MMIO, so that the same code can be used in a later patch for guest KSeg0 addresses (TLB exception handling) as well as for host KSeg1 addresses (existing address error exception and TLB exception handling). We now use kvm_mips_emulate_store() and kvm_mips_emulate_load() directly rather than the more generic kvm_mips_emulate_inst(), as there is no need to expose emulation of any other instructions. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/kvm/trap_emul.c | 119 +++++++++++++++++++++++--------------- 1 file changed, 72 insertions(+), 47 deletions(-) diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c index 070d1ddbc7ee..ae971ae30e30 100644 --- a/arch/mips/kvm/trap_emul.c +++ b/arch/mips/kvm/trap_emul.c @@ -85,6 +85,75 @@ static int kvm_trap_emul_handle_cop_unusable(struct kvm_vcpu *vcpu) return ret; } +static int kvm_mips_bad_load(u32 cause, u32 *opc, struct kvm_run *run, + struct kvm_vcpu *vcpu) +{ + enum emulation_result er; + union mips_instruction inst; + int err; + + /* A code fetch fault doesn't count as an MMIO */ + if (kvm_is_ifetch_fault(&vcpu->arch)) { + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + return RESUME_HOST; + } + + /* Fetch the instruction. */ + if (cause & CAUSEF_BD) + opc += 1; + err = kvm_get_badinstr(opc, vcpu, &inst.word); + if (err) { + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + return RESUME_HOST; + } + + /* Emulate the load */ + er = kvm_mips_emulate_load(inst, cause, run, vcpu); + if (er == EMULATE_FAIL) { + kvm_err("Emulate load from MMIO space failed\n"); + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + } else { + run->exit_reason = KVM_EXIT_MMIO; + } + return RESUME_HOST; +} + +static int kvm_mips_bad_store(u32 cause, u32 *opc, struct kvm_run *run, + struct kvm_vcpu *vcpu) +{ + enum emulation_result er; + union mips_instruction inst; + int err; + + /* Fetch the instruction. */ + if (cause & CAUSEF_BD) + opc += 1; + err = kvm_get_badinstr(opc, vcpu, &inst.word); + if (err) { + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + return RESUME_HOST; + } + + /* Emulate the store */ + er = kvm_mips_emulate_store(inst, cause, run, vcpu); + if (er == EMULATE_FAIL) { + kvm_err("Emulate store to MMIO space failed\n"); + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + } else { + run->exit_reason = KVM_EXIT_MMIO; + } + return RESUME_HOST; +} + +static int kvm_mips_bad_access(u32 cause, u32 *opc, struct kvm_run *run, + struct kvm_vcpu *vcpu, bool store) +{ + if (store) + return kvm_mips_bad_store(cause, opc, run, vcpu); + else + return kvm_mips_bad_load(cause, opc, run, vcpu); +} + static int kvm_trap_emul_handle_tlb_mod(struct kvm_vcpu *vcpu) { struct kvm_run *run = vcpu->run; @@ -178,28 +247,11 @@ static int kvm_trap_emul_handle_tlb_miss(struct kvm_vcpu *vcpu, bool store) } } else if (KVM_GUEST_KERNEL_MODE(vcpu) && (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1)) { - /* A code fetch fault doesn't count as an MMIO */ - if (!store && kvm_is_ifetch_fault(&vcpu->arch)) { - run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - return RESUME_HOST; - } - /* * With EVA we may get a TLB exception instead of an address * error when the guest performs MMIO to KSeg1 addresses. */ - kvm_debug("Emulate %s MMIO space\n", - store ? "Store to" : "Load from"); - er = kvm_mips_emulate_inst(cause, opc, run, vcpu); - if (er == EMULATE_FAIL) { - kvm_err("Emulate %s MMIO space failed\n", - store ? "Store to" : "Load from"); - run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - ret = RESUME_HOST; - } else { - run->exit_reason = KVM_EXIT_MMIO; - ret = RESUME_HOST; - } + ret = kvm_mips_bad_access(cause, opc, run, vcpu, store); } else { kvm_err("Illegal TLB %s fault address , cause %#x, PC: %p, BadVaddr: %#lx\n", store ? "ST" : "LD", cause, opc, badvaddr); @@ -227,21 +279,11 @@ static int kvm_trap_emul_handle_addr_err_st(struct kvm_vcpu *vcpu) u32 __user *opc = (u32 __user *) vcpu->arch.pc; unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr; u32 cause = vcpu->arch.host_cp0_cause; - enum emulation_result er = EMULATE_DONE; int ret = RESUME_GUEST; if (KVM_GUEST_KERNEL_MODE(vcpu) && (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1)) { - kvm_debug("Emulate Store to MMIO space\n"); - er = kvm_mips_emulate_inst(cause, opc, run, vcpu); - if (er == EMULATE_FAIL) { - kvm_err("Emulate Store to MMIO space failed\n"); - run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - ret = RESUME_HOST; - } else { - run->exit_reason = KVM_EXIT_MMIO; - ret = RESUME_HOST; - } + ret = kvm_mips_bad_store(cause, opc, run, vcpu); } else { kvm_err("Address Error (STORE): cause %#x, PC: %p, BadVaddr: %#lx\n", cause, opc, badvaddr); @@ -257,32 +299,15 @@ static int kvm_trap_emul_handle_addr_err_ld(struct kvm_vcpu *vcpu) u32 __user *opc = (u32 __user *) vcpu->arch.pc; unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr; u32 cause = vcpu->arch.host_cp0_cause; - enum emulation_result er = EMULATE_DONE; int ret = RESUME_GUEST; if (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1) { - /* A code fetch fault doesn't count as an MMIO */ - if (kvm_is_ifetch_fault(&vcpu->arch)) { - run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - return RESUME_HOST; - } - - kvm_debug("Emulate Load from MMIO space @ %#lx\n", badvaddr); - er = kvm_mips_emulate_inst(cause, opc, run, vcpu); - if (er == EMULATE_FAIL) { - kvm_err("Emulate Load from MMIO space failed\n"); - run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - ret = RESUME_HOST; - } else { - run->exit_reason = KVM_EXIT_MMIO; - ret = RESUME_HOST; - } + ret = kvm_mips_bad_load(cause, opc, run, vcpu); } else { kvm_err("Address Error (LOAD): cause %#x, PC: %p, BadVaddr: %#lx\n", cause, opc, badvaddr); run->exit_reason = KVM_EXIT_INTERNAL_ERROR; ret = RESUME_HOST; - er = EMULATE_FAIL; } return ret; } -- 2.20.1