Re: [PATCH] KVM: MMU: Fix overflow of SHADOW_PT_INDEX with EPT in 32pae

[Avi Kivity <avi@qumranet.com>]

Yang, Sheng wrote:
> From: Sheng Yang <sheng.yang@intel.com>
> Date: Mon, 1 Sep 2008 17:28:59 +0800
> Subject: [PATCH] KVM: MMU: Fix overflow of SHADOW_PT_INDEX with EPT in 32pae
>
> EPT is 4 level by default in 32pae (48bits), but virtual address only
> got 32 bits. This result in SHADOW_PT_INDEX() overflow when try to
> fetch level 4 index.
>
> Fix it by extend virtual address to 64bits in any condition.
>
>   

Good catch.

> Signed-off-by: Sheng Yang <sheng.yang@intel.com>
> ---
>  arch/x86/kvm/mmu.c |    8 +++++++-
>  1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index f33c594..8ca9aad 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -943,6 +943,7 @@ static int walk_shadow(struct kvm_shadow_walk *walker,
>  	int level;
>  	int r;
>  	u64 *sptep;
> +	u64 ext_addr = addr;
>   

addr isn't really a gva_t; it is a pga_t when using direct mappings.

So how about changing walk_shadow() and its callbacks to use u64 instead 
of gva_t instead?


-- 
error compiling committee.c: too many arguments to function