KVM: MIPS/T&E: Abstract bad access handling

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 <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index 070d1dd..ae971ae 100644 (file)
--- 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;
 }