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KVM: x86: fix checking of cr0 validity

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Move to/from Control Registers chapter of Intel SDM says.  "Reserved bits
in CR0 remain clear after any load of those registers; attempts to set
them have no impact". Control Register chapter says "Bits 63:32 of CR0 are
reserved and must be written with zeros. Writing a nonzero value to any
of the upper 32 bits results in a general-protection exception, #GP(0)."

This patch tries to implement this twisted logic.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Gleb Natapov 2010-01-21 15:28:46 +02:00 committed by Marcelo Tosatti
parent f0f4b93090
commit ab344828eb
1 changed files with 5 additions and 1 deletions
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6
arch/x86/kvm/x86.c
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@ -430,12 +430,16 @@ void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
cr0 |= X86_CR0_ET;
if (cr0 & CR0_RESERVED_BITS) {
#ifdef CONFIG_X86_64
if (cr0 & 0xffffffff00000000UL) {
printk(KERN_DEBUG "set_cr0: 0x%lx #GP, reserved bits 0x%lx\n",
cr0, kvm_read_cr0(vcpu));
kvm_inject_gp(vcpu, 0);
return;
}
#endif
cr0 &= ~CR0_RESERVED_BITS;
if ((cr0 & X86_CR0_NW) && !(cr0 & X86_CR0_CD)) {
printk(KERN_DEBUG "set_cr0: #GP, CD == 0 && NW == 1\n");