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power/mm: update pte_write and pte_wrprotect to handle savedwrite

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We use pte_write() to check whethwer the pte entry is writable.  This is
mostly used to later mark the pte read only if it is writable.  The other
use of pte_write() is to check whether the pte_entry is writable so that
hardware page table entry can be marked accordingly.  This is used in kvm
where we look at qemu page table entry and update hardware hash page table
for the guest with correct write enable bit.

With the above, for the first usage we should also check the savedwrite
bit so that we can correctly clear the savedwite bit.  For the later, we
add a new variant __pte_write().

With this we can revert write_protect_page part of 595cd8f256 ("mm/ksm:
handle protnone saved writes when making page write protect").  But I left
it as it is as an example code for savedwrite check.

Fixes: c137a2757b ("powerpc/mm/autonuma: switch ppc64 to its own implementation of saved write")
Link: http://lkml.kernel.org/r/1488203787-17849-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Aneesh Kumar K.V
2017-03-09 16:16:39 -08:00
committed by Linus Torvalds
parent 52c50ca75c
commit d19469e841
3 changed files with 21 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/kvm/book3s_64_mmu_hv.c
View File

@@ -601,7 +601,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
hva, NULL, NULL);
if (ptep) {
pte = kvmppc_read_update_linux_pte(ptep, 1);
if (pte_write(pte))
if (__pte_write(pte))
write_ok = 1;
}
local_irq_restore(flags);

2
arch/powerpc/kvm/book3s_hv_rm_mmu.c
View File

@@ -256,7 +256,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
}
pte = kvmppc_read_update_linux_pte(ptep, writing);
if (pte_present(pte) && !pte_protnone(pte)) {
if (writing && !pte_write(pte))
if (writing && !__pte_write(pte))
/* make the actual HPTE be read-only */
ptel = hpte_make_readonly(ptel);
is_ci = pte_ci(pte);