From: Leonardo Bras <leonardo@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org
Cc: Leonardo Bras <leonardo@linux.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Arnd Bergmann <arnd@arndb.de>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Andrew Morton <akpm@linux-foundation.org>,
Dan Williams <dan.j.williams@intel.com>,
Nicholas Piggin <npiggin@gmail.com>,
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
Allison Randal <allison@lohutok.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ganesh Goudar <ganeshgr@linux.ibm.com>,
Mike Rapoport <rppt@linux.ibm.com>,
YueHaibing <yuehaibing@huawei.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ira Weiny <ira.weiny@intel.com>, Jason Gunthorpe <jgg@ziepe.ca>,
John Hubbard <jhubbard@nvidia.com>,
Keith Busch <keith.busch@intel.com>
Subject: [PATCH v4 09/11] powerpc/kvm/book3s_64: Applies counting method to monitor lockless pgtbl walks
Date: Fri, 27 Sep 2019 20:40:06 -0300 [thread overview]
Message-ID: <20190927234008.11513-10-leonardo@linux.ibm.com> (raw)
In-Reply-To: <20190927234008.11513-1-leonardo@linux.ibm.com>
Applies the counting-based method for monitoring all book3s_64-related
functions that do lockless pagetable walks.
Adds comments explaining that some lockless pagetable walks don't need
protection due to guest pgd not being a target of THP collapse/split, or
due to being called from Realmode + MSR_EE = 0.
Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 2 ++
arch/powerpc/kvm/book3s_64_mmu_radix.c | 30 ++++++++++++++++++++++++++
arch/powerpc/kvm/book3s_64_vio_hv.c | 3 +++
3 files changed, 35 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 9a75f0e1933b..fcd3dad1297f 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -620,6 +620,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
* We need to protect against page table destruction
* hugepage split and collapse.
*/
+ start_lockless_pgtbl_walk(kvm->mm);
local_irq_save(flags);
ptep = find_current_mm_pte(current->mm->pgd,
hva, NULL, NULL);
@@ -629,6 +630,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
write_ok = 1;
}
local_irq_restore(flags);
+ end_lockless_pgtbl_walk(kvm->mm);
}
}
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 2d415c36a61d..9b374b9838fa 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -813,6 +813,7 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
* Read the PTE from the process' radix tree and use that
* so we get the shift and attribute bits.
*/
+ start_lockless_pgtbl_walk(kvm->mm);
local_irq_disable();
ptep = __find_linux_pte(vcpu->arch.pgdir, hva, NULL, &shift);
/*
@@ -821,12 +822,14 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
*/
if (!ptep) {
local_irq_enable();
+ end_lockless_pgtbl_walk(kvm->mm);
if (page)
put_page(page);
return RESUME_GUEST;
}
pte = *ptep;
local_irq_enable();
+ end_lockless_pgtbl_walk(kvm->mm);
/* If we're logging dirty pages, always map single pages */
large_enable = !(memslot->flags & KVM_MEM_LOG_DIRTY_PAGES);
@@ -972,10 +975,16 @@ int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned long gpa = gfn << PAGE_SHIFT;
unsigned int shift;
+ /*
+ * We are walking the secondary (partition-scoped) page table here.
+ * We can do this without disabling irq because the Linux MM
+ * subsystem doesn't do THP splits and collapses on this tree.
+ */
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep))
kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot,
kvm->arch.lpid);
+
return 0;
}
@@ -989,6 +998,11 @@ int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
int ref = 0;
unsigned long old, *rmapp;
+ /*
+ * We are walking the secondary (partition-scoped) page table here.
+ * We can do this without disabling irq because the Linux MM
+ * subsystem doesn't do THP splits and collapses on this tree.
+ */
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
@@ -1013,6 +1027,11 @@ int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned int shift;
int ref = 0;
+ /*
+ * We are walking the secondary (partition-scoped) page table here.
+ * We can do this without disabling irq because the Linux MM
+ * subsystem doesn't do THP splits and collapses on this tree.
+ */
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_young(*ptep))
ref = 1;
@@ -1030,6 +1049,11 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm,
int ret = 0;
unsigned long old, *rmapp;
+ /*
+ * We are walking the secondary (partition-scoped) page table here.
+ * We can do this without disabling irq because the Linux MM
+ * subsystem doesn't do THP splits and collapses on this tree.
+ */
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
ret = 1;
@@ -1046,6 +1070,7 @@ static int kvm_radix_test_clear_dirty(struct kvm *kvm,
1UL << shift);
spin_unlock(&kvm->mmu_lock);
}
+
return ret;
}
@@ -1085,6 +1110,11 @@ void kvmppc_radix_flush_memslot(struct kvm *kvm,
gpa = memslot->base_gfn << PAGE_SHIFT;
spin_lock(&kvm->mmu_lock);
for (n = memslot->npages; n; --n) {
+ /*
+ * We are walking the secondary (partition-scoped) page table here.
+ * We can do this without disabling irq because the Linux MM
+ * subsystem doesn't do THP splits and collapses on this tree.
+ */
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep))
kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot,
diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index b4f20f13b860..376d069a92dd 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -431,6 +431,7 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu,
unsigned long ua, unsigned long *phpa)
{
+ struct kvm *kvm = vcpu->kvm;
pte_t *ptep, pte;
unsigned shift = 0;
@@ -443,10 +444,12 @@ static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu,
* to exit which will agains result in the below page table walk
* to finish.
*/
+ start_lockless_pgtbl_walk(kvm->mm);
ptep = __find_linux_pte(vcpu->arch.pgdir, ua, NULL, &shift);
if (!ptep || !pte_present(*ptep))
return -ENXIO;
pte = *ptep;
+ end_lockless_pgtbl_walk(kvm->mm);
if (!shift)
shift = PAGE_SHIFT;
--
2.20.1
next prev parent reply other threads:[~2019-09-27 23:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-27 23:39 [PATCH v4 00/11] Introduces new count-based method for monitoring lockless pagetable walks Leonardo Bras
2019-09-27 23:39 ` [PATCH v4 01/11] powerpc/mm: Adds counting method to monitor lockless pgtable walks Leonardo Bras
[not found] ` <4ff1e8e8-929b-9cfc-9bf8-ee88e34de888@nvidia.com>
2019-09-30 15:14 ` Leonardo Bras
[not found] ` <48bf32ca-5d3e-5d69-4cd1-6720364a0d81@nvidia.com>
2019-09-30 18:42 ` Leonardo Bras
[not found] ` <8534727b-72ed-b974-219e-02155bcd17a8@nvidia.com>
2019-10-01 18:39 ` Leonardo Bras
2019-09-27 23:39 ` [PATCH v4 02/11] asm-generic/pgtable: Adds dummy functions " Leonardo Bras
2019-09-27 23:40 ` [PATCH v4 03/11] mm/gup: Applies counting method to monitor gup_pgd_range Leonardo Bras
2019-09-30 11:09 ` Kirill A. Shutemov
2019-09-30 14:27 ` Leonardo Bras
[not found] ` <ce0a4110-9f83-36db-dc85-6a727d30d030@nvidia.com>
2019-10-01 17:56 ` Leonardo Bras
[not found] ` <a5e86058-7950-b832-b042-8cc864de761d@nvidia.com>
2019-10-01 19:40 ` Leonardo Bras
2019-09-27 23:40 ` [PATCH v4 04/11] powerpc/mce_power: Applies counting method to monitor lockless pgtbl walks Leonardo Bras
2019-09-27 23:40 ` [PATCH v4 05/11] powerpc/perf: " Leonardo Bras
2019-09-27 23:40 ` [PATCH v4 06/11] powerpc/mm/book3s64/hash: " Leonardo Bras
2019-09-27 23:40 ` [PATCH v4 07/11] powerpc/kvm/e500: " Leonardo Bras
2019-09-27 23:40 ` [PATCH v4 08/11] powerpc/kvm/book3s_hv: " Leonardo Bras
2019-09-27 23:40 ` Leonardo Bras [this message]
2019-09-27 23:40 ` [PATCH v4 10/11] powerpc/book3s_64: Enables counting method to monitor lockless pgtbl walk Leonardo Bras
2019-09-27 23:40 ` [PATCH v4 11/11] powerpc/mm/book3s64/pgtable: Uses counting method to skip serializing Leonardo Bras
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