From ab344828ebe729e52949d64046adaa196f6b9dbe Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Thu, 21 Jan 2010 15:28:46 +0200 Subject: KVM: x86: fix checking of cr0 validity 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 Reported-by: Lorenzo Martignoni Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/x86.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fd5101b57fa..ce267d9f030 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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"); -- cgit v1.2.3