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powerpc/mm: Rename find_linux_pte_or_hugepte()

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Add newer helpers to make the function usage simpler. It is always
recommended to use find_current_mm_pte() for walking the page table.
If we cannot use find_current_mm_pte(), it should be documented why
the said usage of __find_linux_pte() is safe against a parallel THP
split.

For now we have KVM code using __find_linux_pte(). This is because kvm
code ends up calling __find_linux_pte() in real mode with MSR_EE=0 but
with PACA soft_enabled = 1. We may want to fix that later and make
sure we keep the MSR_EE and PACA soft_enabled in sync. When we do that
we can switch kvm to use find_linux_pte().

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V
2017-07-27 11:54:53 +05:30
committed by Michael Ellerman
parent 520eccdfe1
commit 94171b19c3
13 changed files with 103 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
arch/powerpc/kvm/book3s_64_mmu_hv.c
View File

@@ -37,6 +37,7 @@
#include <asm/synch.h>
#include <asm/ppc-opcode.h>
#include <asm/cputable.h>
#include <asm/pte-walk.h>
#include "trace_hv.h"
@@ -597,8 +598,8 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
* hugepage split and collapse.
*/
local_irq_save(flags);
ptep = find_linux_pte_or_hugepte(current->mm->pgd,
hva, NULL, NULL);
ptep = find_current_mm_pte(current->mm->pgd,
hva, NULL, NULL);
if (ptep) {
pte = kvmppc_read_update_linux_pte(ptep, 1);
if (__pte_write(pte))

28
arch/powerpc/kvm/book3s_64_mmu_radix.c
View File

@@ -17,6 +17,7 @@
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/pte-walk.h>
/*
* Supported radix tree geometry.
@@ -359,8 +360,7 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
if (writing)
pgflags |= _PAGE_DIRTY;
local_irq_save(flags);
ptep = __find_linux_pte_or_hugepte(current->mm->pgd, hva,
NULL, NULL);
ptep = find_current_mm_pte(current->mm->pgd, hva, NULL, NULL);
if (ptep) {
pte = READ_ONCE(*ptep);
if (pte_present(pte) &&
@@ -374,8 +374,12 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
spin_unlock(&kvm->mmu_lock);
return RESUME_GUEST;
}
ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable,
gpa, NULL, &shift);
/*
* We are walking the secondary page table here. We can do this
* without disabling irq.
*/
ptep = __find_linux_pte(kvm->arch.pgtable,
gpa, NULL, &shift);
if (ptep && pte_present(*ptep)) {
kvmppc_radix_update_pte(kvm, ptep, 0, pgflags,
gpa, shift);
@@ -427,8 +431,8 @@ int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
pgflags |= _PAGE_WRITE;
} else {
local_irq_save(flags);
ptep = __find_linux_pte_or_hugepte(current->mm->pgd,
hva, NULL, NULL);
ptep = find_current_mm_pte(current->mm->pgd,
hva, NULL, NULL);
if (ptep && pte_write(*ptep) && pte_dirty(*ptep))
pgflags |= _PAGE_WRITE;
local_irq_restore(flags);
@@ -499,8 +503,7 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned int shift;
unsigned long old;
ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
NULL, &shift);
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep)) {
old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0,
gpa, shift);
@@ -525,8 +528,7 @@ int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned int shift;
int ref = 0;
ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
NULL, &shift);
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
gpa, shift);
@@ -545,8 +547,7 @@ int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned int shift;
int ref = 0;
ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
NULL, &shift);
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_young(*ptep))
ref = 1;
return ref;
@@ -562,8 +563,7 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm,
unsigned int shift;
int ret = 0;
ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
NULL, &shift);
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
ret = 1;
if (shift)

12
arch/powerpc/kvm/book3s_64_vio_hv.c
View File

@@ -39,6 +39,7 @@
#include <asm/udbg.h>
#include <asm/iommu.h>
#include <asm/tce.h>
#include <asm/pte-walk.h>
#ifdef CONFIG_BUG
@@ -353,7 +354,16 @@ static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu,
pte_t *ptep, pte;
unsigned shift = 0;
ptep = __find_linux_pte_or_hugepte(vcpu->arch.pgdir, ua, NULL, &shift);
/*
* Called in real mode with MSR_EE = 0. We are safe here.
* It is ok to do the lookup with arch.pgdir here, because
* we are doing this on secondary cpus and current task there
* is not the hypervisor. Also this is safe against THP in the
* host, because an IPI to primary thread will wait for the secondary
* to exit which will agains result in the below page table walk
* to finish.
*/
ptep = __find_linux_pte(vcpu->arch.pgdir, ua, NULL, &shift);
if (!ptep || !pte_present(*ptep))
return -ENXIO;
pte = *ptep;

18
arch/powerpc/kvm/book3s_hv_rm_mmu.c
View File

@@ -22,6 +22,7 @@
#include <asm/hvcall.h>
#include <asm/synch.h>
#include <asm/ppc-opcode.h>
#include <asm/pte-walk.h>
/* Translate address of a vmalloc'd thing to a linear map address */
static void *real_vmalloc_addr(void *x)
@@ -31,9 +32,9 @@ static void *real_vmalloc_addr(void *x)
/*
* assume we don't have huge pages in vmalloc space...
* So don't worry about THP collapse/split. Called
* Only in realmode, hence won't need irq_save/restore.
* Only in realmode with MSR_EE = 0, hence won't need irq_save/restore.
*/
p = __find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL, NULL);
p = find_init_mm_pte(addr, NULL);
if (!p || !pte_present(*p))
return NULL;
addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
@@ -230,14 +231,13 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
* If we had a page table table change after lookup, we would
* retry via mmu_notifier_retry.
*/
if (realmode)
ptep = __find_linux_pte_or_hugepte(pgdir, hva, NULL,
&hpage_shift);
else {
if (!realmode)
local_irq_save(irq_flags);
ptep = find_linux_pte_or_hugepte(pgdir, hva, NULL,
&hpage_shift);
}
/*
* If called in real mode we have MSR_EE = 0. Otherwise
* we disable irq above.
*/
ptep = __find_linux_pte(pgdir, hva, NULL, &hpage_shift);
if (ptep) {
pte_t pte;
unsigned int host_pte_size;

3
arch/powerpc/kvm/e500_mmu_host.c
View File

@@ -30,6 +30,7 @@
#include <linux/vmalloc.h>
#include <linux/hugetlb.h>
#include <asm/kvm_ppc.h>
#include <asm/pte-walk.h>
#include "e500.h"
#include "timing.h"
@@ -476,7 +477,7 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
* can't run hence pfn won't change.
*/
local_irq_save(flags);
ptep = find_linux_pte_or_hugepte(pgdir, hva, NULL, NULL);
ptep = find_linux_pte(pgdir, hva, NULL, NULL);
if (ptep) {
pte_t pte = READ_ONCE(*ptep);