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authorJames Hogan <james.hogan@imgtec.com>2016-07-08 11:53:26 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2016-08-01 18:42:24 +0200
commit2a06dab877dee3d4144c3ba32c662db18a1fdd2b (patch)
tree70073a52c9257c1462f9fd9d9a15ca73e68df94d /arch/mips
parent0d17aea5c27d7d748b1d8116d275b2b17dc5cad6 (diff)
downloadlinux-2a06dab877dee3d4144c3ba32c662db18a1fdd2b.tar.bz2
MIPS: KVM: Fail if ebase doesn't fit in CP0_EBase
Fail if the address of the allocated exception base doesn't fit into the CP0_EBase register. This can happen on MIPS64 if CP0_EBase.WG isn't implemented but RAM is available outside of the range of KSeg0. 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: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/kvm/mips.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 414b00074e29..a6ea084b4d9d 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -300,6 +300,18 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
kvm_debug("Allocated %d bytes for KVM Exception Handlers @ %p\n",
ALIGN(size, PAGE_SIZE), gebase);
+ /*
+ * Check new ebase actually fits in CP0_EBase. The lack of a write gate
+ * limits us to the low 512MB of physical address space. If the memory
+ * we allocate is out of range, just give up now.
+ */
+ if (!cpu_has_ebase_wg && virt_to_phys(gebase) >= 0x20000000) {
+ kvm_err("CP0_EBase.WG required for guest exception base %pK\n",
+ gebase);
+ err = -ENOMEM;
+ goto out_free_gebase;
+ }
+
/* Save new ebase */
vcpu->arch.guest_ebase = gebase;