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MIPS: KVM: Fail if ebase doesn't fit in CP0_EBase

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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>
This commit is contained in:
James Hogan 2016-07-08 11:53:26 +01:00 committed by Paolo Bonzini
parent 0d17aea5c2
commit 2a06dab877
1 changed files with 12 additions and 0 deletions
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12
arch/mips/kvm/mips.c
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@ -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;