Il 18/08/2014 11:50, Wanpeng Li ha scritto:
> EPT misconfig handler in kvm will check which reason lead to EPT
> misconfiguration after vmexit. One of the reasons is that an EPT
> paging-structure entry is configured with settings reserved for
> future functionality. However, the handler can't identify if
> paging-structure entry of reserved bits for 1-GByte page are
> configured, since PDPTE which point to 1-GByte page will reserve
> bits 29:12 instead of bits 7:3 which are reserved for PDPTE that
> references an EPT Page Directory. This patch fix it by reserve
> bits 29:12 for 1-GByte page.
>
> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index bfe11cf..71cbee5 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -5521,9 +5521,14 @@ static u64 ept_rsvd_mask(u64 spte, int level)
> for (i = 51; i > boot_cpu_data.x86_phys_bits; i--)
> mask |= (1ULL << i);
>
> - if (level > 2)
> - /* bits 7:3 reserved */
> - mask |= 0xf8;
> + if (level > 2) {
level can be 4 here. You have to return 0xf8 for level == 4.
The same "if" statement then can cover both 2MB and 1GB pages, like
if (spte & (1ULL << 7))
/* 1GB/2MB page, bits 29:12 or 20:12 reserved respectively */
mask |= (PAGE_SIZE << ((level - 1) * 9)) - PAGE_SIZE;
else
/* bits 6:3 reserved */
mask |= 0x78;
> - if (level == 1 || (level == 2 && (spte & (1ULL << 7)))) {
> + if (level == 1 || ((level == 3 || level == 2)
> + && (spte & (1ULL << 7)))) {
This condition can be simplified by checking the return value of ept_rsvd_mask.
If it includes 0x38, this is a large page. Otherwise it is a leaf page and
you can go down the "if".
Paolo
> u64 ept_mem_type = (spte & 0x38) >> 3;
>
> if (ept_mem_type == 2 || ept_mem_type == 3 ||
>
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