From 7f5a1ddc792901249c2060e165bcb3ca779cde35 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Thu, 9 Jun 2016 10:50:44 +0100 Subject: [PATCH] MIPS: KVM: Include bit 31 in segment matches MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Ralf Baechle Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Paolo Bonzini --- arch/mips/include/asm/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index 2d5bb133d11a..36a391d289aa 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)