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

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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
This commit is contained in:
James Hogan 2016-12-06 19:27:18 +00:00
parent 577ed7f71e
commit 420ea09b64
1 changed files with 72 additions and 47 deletions
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119
arch/mips/kvm/trap_emul.c
View File

@ -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;
}