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    Subject[patch 29/71] KVM: x86: verify MTRR/PAT validity
    2.6.30-stable review patch.  If anyone has any objections, please let us know.

    ------------------
    From: Marcelo Tosatti <mtosatti@redhat.com>

    (cherry picked from commit d6289b9365c3f622a8cfe62c4fb054bb70b5061a)

    Do not allow invalid memory types in MTRR/PAT (generating a #GP
    otherwise).

    Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
    Signed-off-by: Avi Kivity <avi@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    ---
    arch/x86/kvm/x86.c | 39 ++++++++++++++++++++++++++++++++++++++-
    1 file changed, 38 insertions(+), 1 deletion(-)

    --- a/arch/x86/kvm/x86.c
    +++ b/arch/x86/kvm/x86.c
    @@ -706,11 +706,48 @@ static bool msr_mtrr_valid(unsigned msr)
    return false;
    }

    +static bool valid_pat_type(unsigned t)
    +{
    + return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */
    +}
    +
    +static bool valid_mtrr_type(unsigned t)
    +{
    + return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
    +}
    +
    +static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
    +{
    + int i;
    +
    + if (!msr_mtrr_valid(msr))
    + return false;
    +
    + if (msr == MSR_IA32_CR_PAT) {
    + for (i = 0; i < 8; i++)
    + if (!valid_pat_type((data >> (i * 8)) & 0xff))
    + return false;
    + return true;
    + } else if (msr == MSR_MTRRdefType) {
    + if (data & ~0xcff)
    + return false;
    + return valid_mtrr_type(data & 0xff);
    + } else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) {
    + for (i = 0; i < 8 ; i++)
    + if (!valid_mtrr_type((data >> (i * 8)) & 0xff))
    + return false;
    + return true;
    + }
    +
    + /* variable MTRRs */
    + return valid_mtrr_type(data & 0xff);
    +}
    +
    static int set_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
    {
    u64 *p = (u64 *)&vcpu->arch.mtrr_state.fixed_ranges;

    - if (!msr_mtrr_valid(msr))
    + if (!mtrr_valid(vcpu, msr, data))
    return 1;

    if (msr == MSR_MTRRdefType) {



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