Commit 28cc5bd5 authored by James Hogan's avatar James Hogan Committed by Paolo Bonzini
Browse files

MIPS: KVM: Use kmap instead of CKSEG0ADDR() 



There are several unportable uses of CKSEG0ADDR() in MIPS KVM, which
implicitly assume that a host physical address will be in the low 512MB
of the physical address space (accessible in KSeg0). These assumptions
don't hold for highmem or on 64-bit kernels.

When interpreting the guest physical address when reading or overwriting
a trapping instruction, use kmap_atomic() to get a usable virtual
address to access guest memory, which is portable to 64-bit and highmem
kernels.

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
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent cfacaced

arch/mips/kvm/dyntrans.c

+11 −6
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


#include <linux/errno.h>

#include <linux/err.h>

#include <linux/highmem.h>

#include <linux/kvm_host.h>

#include <linux/module.h>

#include <linux/vmalloc.h>
@@ -29,14 +30,18 @@ 
static int kvm_mips_trans_replace(struct kvm_vcpu *vcpu, u32 *opc,

				  union mips_instruction replace)

{

	unsigned long kseg0_opc, flags;

	unsigned long paddr, flags;

	void *vaddr;



	if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {

		kseg0_opc =

		    CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa

			       (vcpu, (unsigned long) opc));

		memcpy((void *)kseg0_opc, (void *)&replace, sizeof(u32));

		local_flush_icache_range(kseg0_opc, kseg0_opc + 32);

		paddr = kvm_mips_translate_guest_kseg0_to_hpa(vcpu,

							    (unsigned long)opc);

		vaddr = kmap_atomic(pfn_to_page(PHYS_PFN(paddr)));

		vaddr += paddr & ~PAGE_MASK;

		memcpy(vaddr, (void *)&replace, sizeof(u32));

		local_flush_icache_range((unsigned long)vaddr,

					 (unsigned long)vaddr + 32);

		kunmap_atomic(vaddr);

	} else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {

		local_irq_save(flags);

		memcpy((void *)opc, (void *)&replace, sizeof(u32));

arch/mips/kvm/mmu.c

+6 −1
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
 * Authors: Sanjay Lal <sanjayl@kymasys.com>

 */



#include <linux/highmem.h>

#include <linux/kvm_host.h>

#include <asm/mmu_context.h>
@@ -330,6 +331,7 @@ u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu) 
	struct mips_coproc *cop0 = vcpu->arch.cop0;

	unsigned long paddr, flags, vpn2, asid;

	unsigned long va = (unsigned long)opc;

	void *vaddr;

	u32 inst;

	int index;
@@ -360,7 +362,10 @@ u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu) 
		local_irq_restore(flags);

	} else if (KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG0) {

		paddr = kvm_mips_translate_guest_kseg0_to_hpa(vcpu, va);

		inst = *(u32 *) CKSEG0ADDR(paddr);

		vaddr = kmap_atomic(pfn_to_page(PHYS_PFN(paddr)));

		vaddr += paddr & ~PAGE_MASK;

		inst = *(u32 *)vaddr;

		kunmap_atomic(vaddr);

	} else {

		kvm_err("%s: illegal address: %p\n", __func__, opc);

		return KVM_INVALID_INST;

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