diff mbox

[BACKPORT,3.17-4.4,2/4] MIPS: KVM: Add missing gfn range check

Message ID 5ae3371dc11534460b722864ea8c6ef27e8506d1.1471018436.git-series.james.hogan@imgtec.com (mailing list archive)
State New, archived
Headers show

Commit Message

James Hogan Aug. 18, 2016, 9:05 a.m. UTC
commit 8985d50382359e5bf118fdbefc859d0dbf6cebc7 upstream.

kvm_mips_handle_mapped_seg_tlb_fault() calculates the guest frame number
based on the guest TLB EntryLo values, however it is not range checked
to ensure it lies within the guest_pmap. If the physical memory the
guest refers to is out of range then dump the guest TLB and emit an
internal error.

Fixes: 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
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
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[james.hogan@imgtec.com: Backport to v3.17.y - v4.4.y]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 arch/mips/kvm/tlb.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

Comments

Levin, Alexander Aug. 18, 2016, 11:45 a.m. UTC | #1
On 08/18/2016 05:05 AM, James Hogan wrote:
> commit 8985d50382359e5bf118fdbefc859d0dbf6cebc7 upstream.

> 

> kvm_mips_handle_mapped_seg_tlb_fault() calculates the guest frame number

> based on the guest TLB EntryLo values, however it is not range checked

> to ensure it lies within the guest_pmap. If the physical memory the

> guest refers to is out of range then dump the guest TLB and emit an

> internal error.

> 

> Fixes: 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.")

> 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

> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

> [james.hogan@imgtec.com: Backport to v3.17.y - v4.4.y]

> Signed-off-by: James Hogan <james.hogan@imgtec.com>


Hey James,

Thanks for the backport!

Applying this one seems to fail with:

$ git apply --reject [PATCH BACKPORT 3.17-4.4 1_4] MIPS: KVM: Fix mapped
fault broken commpage handling - James Hogan <james.hogan@imgtec.com> -
2016-08-18 0505.eml
Checking patch arch/mips/kvm/tlb.c...
error: while searching for:
	unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
	struct kvm *kvm = vcpu->kvm;
	pfn_t pfn0, pfn1;
	long tlb_lo[2];

	tlb_lo[0] = tlb->tlb_lo0;

error: patch failed: arch/mips/kvm/tlb.c:361
error: while searching for:
			VPN2_MASK & (PAGE_MASK << 1)))
		tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;

	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[0])
				   >> PAGE_SHIFT) < 0)

		return -1;

	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[1])
				   >> PAGE_SHIFT) < 0)

		return -1;

	pfn0 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[0])
				    >> PAGE_SHIFT];

	pfn1 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[1])
				    >> PAGE_SHIFT];


	if (hpa0)
		*hpa0 = pfn0 << PAGE_SHIFT;

error: patch failed: arch/mips/kvm/tlb.c:374
Applying patch arch/mips/kvm/tlb.c with 2 rejects...
Rejected hunk #1.
Rejected hunk #2.


Thanks,
Sasha
Levin, Alexander Aug. 18, 2016, 11:46 a.m. UTC | #2
On 08/18/2016 07:45 AM, Sasha Levin wrote:
> On 08/18/2016 05:05 AM, James Hogan wrote:

>> > commit 8985d50382359e5bf118fdbefc859d0dbf6cebc7 upstream.

>> > 

>> > kvm_mips_handle_mapped_seg_tlb_fault() calculates the guest frame number

>> > based on the guest TLB EntryLo values, however it is not range checked

>> > to ensure it lies within the guest_pmap. If the physical memory the

>> > guest refers to is out of range then dump the guest TLB and emit an

>> > internal error.

>> > 

>> > Fixes: 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.")

>> > 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

>> > Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

>> > [james.hogan@imgtec.com: Backport to v3.17.y - v4.4.y]

>> > Signed-off-by: James Hogan <james.hogan@imgtec.com>

> Hey James,

> 

> Thanks for the backport!

> 

> Applying this one seems to fail with:


*Applying to this one to 4.1, sorry.


Thanks,
Sasha
James Hogan Aug. 18, 2016, 12:31 p.m. UTC | #3
Hi Sasha,

On Thu, Aug 18, 2016 at 07:45:33AM -0400, Levin, Alexander wrote:
> On 08/18/2016 05:05 AM, James Hogan wrote:
> > commit 8985d50382359e5bf118fdbefc859d0dbf6cebc7 upstream.
> > 
> > kvm_mips_handle_mapped_seg_tlb_fault() calculates the guest frame number
> > based on the guest TLB EntryLo values, however it is not range checked
> > to ensure it lies within the guest_pmap. If the physical memory the
> > guest refers to is out of range then dump the guest TLB and emit an
> > internal error.
> > 
> > Fixes: 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
> > 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
> > Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> > [james.hogan@imgtec.com: Backport to v3.17.y - v4.4.y]
> > Signed-off-by: James Hogan <james.hogan@imgtec.com>
> 
> Hey James,
> 
> Thanks for the backport!
> 
> Applying this one seems to fail with:
> 
> $ git apply --reject [PATCH BACKPORT 3.17-4.4 1_4] MIPS: KVM: Fix mapped
> fault broken commpage handling - James Hogan <james.hogan@imgtec.com> -
> 2016-08-18 0505.eml
> Checking patch arch/mips/kvm/tlb.c...
> error: while searching for:
> 	unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
> 	struct kvm *kvm = vcpu->kvm;
> 	pfn_t pfn0, pfn1;
> 	long tlb_lo[2];
> 
> 	tlb_lo[0] = tlb->tlb_lo0;
> 
> error: patch failed: arch/mips/kvm/tlb.c:361
> error: while searching for:
> 			VPN2_MASK & (PAGE_MASK << 1)))
> 		tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;
> 
> 	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[0])
> 				   >> PAGE_SHIFT) < 0)
> 		return -1;
> 
> 	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[1])
> 				   >> PAGE_SHIFT) < 0)
> 		return -1;
> 
> 	pfn0 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[0])
> 				    >> PAGE_SHIFT];
> 	pfn1 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[1])
> 				    >> PAGE_SHIFT];
> 
> 	if (hpa0)
> 		*hpa0 = pfn0 << PAGE_SHIFT;
> 
> error: patch failed: arch/mips/kvm/tlb.c:374
> Applying patch arch/mips/kvm/tlb.c with 2 rejects...
> Rejected hunk #1.
> Rejected hunk #2.

This works for me (on 558ba5fd7d8d Linux 4.1.30) as long as 1/4 is
applied first. Are you applying them in the right order?

Cheers
James
diff mbox

Patch

diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c
index d3c5715426c4..59e885fa4c65 100644
--- a/arch/mips/kvm/tlb.c
+++ b/arch/mips/kvm/tlb.c
@@ -361,6 +361,7 @@  int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
 	unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
 	struct kvm *kvm = vcpu->kvm;
 	pfn_t pfn0, pfn1;
+	gfn_t gfn0, gfn1;
 	long tlb_lo[2];
 
 	tlb_lo[0] = tlb->tlb_lo0;
@@ -374,18 +375,24 @@  int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
 			VPN2_MASK & (PAGE_MASK << 1)))
 		tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;
 
-	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[0])
-				   >> PAGE_SHIFT) < 0)
+	gfn0 = mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT;
+	gfn1 = mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT;
+	if (gfn0 >= kvm->arch.guest_pmap_npages ||
+	    gfn1 >= kvm->arch.guest_pmap_npages) {
+		kvm_err("%s: Invalid gfn: [%#llx, %#llx], EHi: %#lx\n",
+			__func__, gfn0, gfn1, tlb->tlb_hi);
+		kvm_mips_dump_guest_tlbs(vcpu);
+		return -1;
+	}
+
+	if (kvm_mips_map_page(kvm, gfn0) < 0)
 		return -1;
 
-	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[1])
-				   >> PAGE_SHIFT) < 0)
+	if (kvm_mips_map_page(kvm, gfn1) < 0)
 		return -1;
 
-	pfn0 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[0])
-				    >> PAGE_SHIFT];
-	pfn1 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[1])
-				    >> PAGE_SHIFT];
+	pfn0 = kvm->arch.guest_pmap[gfn0];
+	pfn1 = kvm->arch.guest_pmap[gfn1];
 
 	if (hpa0)
 		*hpa0 = pfn0 << PAGE_SHIFT;