KVM: MIPS: Emulate MMIO via TLB miss for EVA (d5888477) · Commits · 戴 / test

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

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);

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