Messages in this thread | | | Date | Fri, 30 Mar 2012 13:01:47 +0800 | From | Xiao Guangrong <> | Subject | Re: [PATCH 04/13] KVM: MMU: introduce FNAME(get_sp_gpa) |
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On 03/29/2012 09:07 PM, Avi Kivity wrote:
> On 03/29/2012 11:22 AM, Xiao Guangrong wrote: >> It can calculate the base gpa of the specified shadow page on any level, >> let it instead of FNAME(get_level1_sp_gpa) >> >> >> +static gpa_t FNAME(get_sp_gpa)(struct kvm_mmu_page *sp) >> +{ > > Maybe worth adding a pte index and calling it get_spte_gpa(), depends on > the next patches I guess. >
Yes.
But FNAME(get_sp_gpa) is still needed by FNAME(sync_page) path which sync all sptes. I will introduce get_spte_gpa() as you mentioned which will be used in invlpg path and in the later patch.
>> + int offset, shift; >> + >> + shift = PAGE_SHIFT - (PT_LEVEL_BITS - PT64_LEVEL_BITS) * sp->role.level; >> + offset = sp->role.quadrant << shift; > > if you add '& ~PAGE_MASK' the compiler may be smart enough to drop the > whole thing for 64-bit ptes. >
Sorry. how to do that?
But if you want to remove the unnecessary workload, i will change it like this:
static gpa_t FNAME(get_sp_gpa)(struct kvm_mmu_page *sp) { int offset = 0;
#if PTTYPE == 32 int shift;
shift = PAGE_SHIFT - (PT_LEVEL_BITS - PT64_LEVEL_BITS) * sp->role.level; offset = sp->role.quadrant << shift; #endif return gfn_to_gpa(sp->gfn) + offset; }
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