MIPS Enhanced Virtual Addressing (EVA) allows the virtual memory
segments to be rearranged such that the KSeg0/KSeg1 segments are
accessible TLB mapped to user mode, which would trigger a TLB Miss
exception (due to lack of TLB mappings) instead of an Address Error
exception.
Update the TLB Miss handling similar to Address Error handling for guest
MMIO emulation.
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
---
arch/mips/kvm/trap_emul.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index 091553942bcb..3a5484f9aa50 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -175,6 +175,24 @@ static int kvm_trap_emul_handle_tlb_miss(struct kvm_vcpu *vcpu, bool store)
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
+ } else if (KVM_GUEST_KERNEL_MODE(vcpu)
+ && (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1)) {
+ /*
+ * 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;
+ }
} else {
kvm_err("Illegal TLB %s fault address , cause %#x, PC: %p, BadVaddr: %#lx\n",
store ? "ST" : "LD", cause, opc, badvaddr);
--
2.7.3
