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authorJames Hogan <james.hogan@imgtec.com>2016-06-09 10:50:44 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2016-06-14 10:59:44 +0200
commit7f5a1ddc792901249c2060e165bcb3ca779cde35 (patch)
tree5f160a24b922d064496a62cc57a2f73d6ed2cd4f
parent797179bc4fe06c89e47a9f36f886f68640b423f8 (diff)
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op-kernel-dev-7f5a1ddc792901249c2060e165bcb3ca779cde35.tar.gz
MIPS: KVM: Include bit 31 in segment matches
When faulting guest addresses are matched against guest segments with the KVM_GUEST_KSEGX() macro, change the mask to 0xe0000000 so as to include bit 31. This is mainly for safety's sake, as it prevents a rogue BadVAddr in the host kseg2/kseg3 segments (e.g. 0xC*******) after a TLB exception from matching the guest kseg0 segment (e.g. 0x4*******), triggering an internal KVM error instead of allowing the corresponding guest kseg0 page to be mapped into the host vmalloc space. Such a rogue BadVAddr was observed to happen with the host MIPS kernel running under QEMU with KVM built as a module, due to a not entirely transparent optimisation in the QEMU TLB handling. This has already been worked around properly in a previous commit. 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: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/mips/include/asm/kvm_host.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 2d5bb13..36a391d 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -74,7 +74,7 @@
#define KVM_GUEST_KUSEG 0x00000000UL
#define KVM_GUEST_KSEG0 0x40000000UL
#define KVM_GUEST_KSEG23 0x60000000UL
-#define KVM_GUEST_KSEGX(a) ((_ACAST32_(a)) & 0x60000000)
+#define KVM_GUEST_KSEGX(a) ((_ACAST32_(a)) & 0xe0000000)
#define KVM_GUEST_CPHYSADDR(a) ((_ACAST32_(a)) & 0x1fffffff)
#define KVM_GUEST_CKSEG0ADDR(a) (KVM_GUEST_CPHYSADDR(a) | KVM_GUEST_KSEG0)
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