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    Subject[patch 142/164] KVM: SVM: Fix nested msr intercept handling
    2.6.33-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Joerg Roedel <joerg.roedel@amd.com>

    The nested_svm_exit_handled_msr() function maps only one
    page of the guests msr permission bitmap. This patch changes
    the code to use kvm_read_guest to fix the bug.

    Cc: stable@kernel.org
    Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
    Signed-off-by: Avi Kivity <avi@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    (cherry picked from commit 4c7da8cb43c09e71a405b5aeaa58a1dbac3c39e9)
    ---
    arch/x86/kvm/svm.c | 13 +++----------
    1 file changed, 3 insertions(+), 10 deletions(-)

    --- a/arch/x86/kvm/svm.c
    +++ b/arch/x86/kvm/svm.c
    @@ -1434,19 +1434,13 @@ static bool nested_svm_exit_handled_msr(
    {
    u32 param = svm->vmcb->control.exit_info_1 & 1;
    u32 msr = svm->vcpu.arch.regs[VCPU_REGS_RCX];
    - struct page *page;
    bool ret = false;
    u32 t0, t1;
    - u8 *msrpm;
    + u8 val;

    if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
    return false;

    - msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, &page);
    -
    - if (!msrpm)
    - goto out;
    -
    switch (msr) {
    case 0 ... 0x1fff:
    t0 = (msr * 2) % 8;
    @@ -1467,11 +1461,10 @@ static bool nested_svm_exit_handled_msr(
    goto out;
    }

    - ret = msrpm[t1] & ((1 << param) << t0);
    + if (!kvm_read_guest(svm->vcpu.kvm, svm->nested.vmcb_msrpm + t1, &val, 1))
    + ret = val & ((1 << param) << t0);

    out:
    - nested_svm_unmap(page);
    -
    return ret;
    }




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