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From: Avi Kivity on 1 Jul 2010 10:20
On 07/01/2010 05:00 PM, Joerg Roedel wrote:
> This patch converts unnecessary divide and modulo operations
> in the KVM large page related code into logical operations.
> This allows to convert gfn_t to u64 while not breaking 32
> bit builds.
>
>
> #define KVM_NR_PAGE_SIZES 2
> -#define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + ((x) - 1) * 8)
> +#define KVM_HPAGE_GFN_SHIFT(x) (((x) - 1) * 8)
> +#define KVM_HPAGE_SHIFT(x) (PAGE_SHIFT + KVM_HPAGE_GFN_SHIFT(x))
> #define KVM_HPAGE_SIZE(x) (1UL<< KVM_HPAGE_SHIFT(x))
> #define KVM_HPAGE_MASK(x) (~(KVM_HPAGE_SIZE(x) - 1))
>

In theory, KVM_HPAGE_SIZE() needs s/1UL/(u64)1/, or KVM_HPAGE_MASK
becomes truncated if used against a gfn_t. In practice, KVM_HPAGE_MASK
is not used at all, so this doesn't matter.

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

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