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Commit d5888477 authored by James Hogan's avatar James Hogan
Browse files

KVM: MIPS: Emulate MMIO via TLB miss for EVA 



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: default avatarJames 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
parent f6f70171

arch/mips/kvm/trap_emul.c

+18 −0
Original line number Diff line number Diff line
@@ -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);