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KVM: MIPS: Emulate MMIO via TLB miss for EVA

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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@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 2016-08-19 15:09:47 +01:00
parent f6f7017192
commit d5888477d3
1 changed files with 18 additions and 0 deletions
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18
arch/mips/kvm/trap_emul.c
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@ -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);