[PATCH v4 01/20] KVM: x86/mmu: Optimize MMU page cache lookup for all direct SPs

[Lai Jiangshan]

On 2022/4/23 05:05, David Matlack wrote:
> Commit fb58a9c345f6 ("KVM: x86/mmu: Optimize MMU page cache lookup for
> fully direct MMUs") skipped the unsync checks and write flood clearing
> for full direct MMUs. We can extend this further to skip the checks for
> all direct shadow pages. Direct shadow pages in indirect MMUs (i.e.
> shadow paging) are used when shadowing a guest huge page with smaller
> pages. Such direct shadow pages, like their counterparts in fully direct
> MMUs, are never marked unsynced or have a non-zero write-flooding count.
>
> Checking sp->role.direct also generates better code than checking
> direct_map because, due to register pressure, direct_map has to get
> shoved onto the stack and then pulled back off.
>
> No functional change intended.
>
> Reviewed-by: Sean Christopherson <seanjc at google.com>
> Reviewed-by: Peter Xu <peterx at redhat.com>
> Signed-off-by: David Matlack <dmatlack at google.com>


Reviewed-by: Lai Jiangshan <jiangshanlai at gmail.com>