From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Marc Zyngier <maz@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, Junaid Shahid <junaids@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
kvm@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
Peter Shier <pshier@google.com>,
linux-mips@vger.kernel.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Ben Gardon <bgardon@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Peter Feiner <pfeiner@google.com>,
kvmarm@lists.cs.columbia.edu, Jim Mattson <jmattson@google.com>
Subject: [PATCH v2 05/21] KVM: x86/mmu: Try to avoid crashing KVM if a MMU memory cache is empty
Date: Mon, 22 Jun 2020 13:08:06 -0700 [thread overview]
Message-ID: <20200622200822.4426-6-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200622200822.4426-1-sean.j.christopherson@intel.com>
Attempt to allocate a new object instead of crashing KVM (and likely the
kernel) if a memory cache is unexpectedly empty. Use GFP_ATOMIC for the
allocation as the caches are used while holding mmu_lock. The immediate
BUG_ON() makes the code unnecessarily explosive and led to confusing
minimums being used in the past, e.g. allocating 4 objects where 1 would
suffice.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ba70de24a5b0..5e773564ab20 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1060,6 +1060,15 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
local_irq_enable();
}
+static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
+ gfp_t gfp_flags)
+{
+ if (mc->kmem_cache)
+ return kmem_cache_zalloc(mc->kmem_cache, gfp_flags);
+ else
+ return (void *)__get_free_page(gfp_flags);
+}
+
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
{
void *obj;
@@ -1067,10 +1076,7 @@ static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
if (mc->nobjs >= min)
return 0;
while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
- if (mc->kmem_cache)
- obj = kmem_cache_zalloc(mc->kmem_cache, GFP_KERNEL_ACCOUNT);
- else
- obj = (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
+ obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
if (!obj)
return mc->nobjs >= min ? 0 : -ENOMEM;
mc->objects[mc->nobjs++] = obj;
@@ -1118,8 +1124,11 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
void *p;
- BUG_ON(!mc->nobjs);
- p = mc->objects[--mc->nobjs];
+ if (WARN_ON(!mc->nobjs))
+ p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
+ else
+ p = mc->objects[--mc->nobjs];
+ BUG_ON(!p);
return p;
}
--
2.26.0
_______________________________________________
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kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
WARNING: multiple messages have this Message-ID (diff)
From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Marc Zyngier <maz@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, Junaid Shahid <junaids@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
kvm@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
Peter Shier <pshier@google.com>,
linux-mips@vger.kernel.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Ben Gardon <bgardon@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Peter Feiner <pfeiner@google.com>,
kvmarm@lists.cs.columbia.edu, Jim Mattson <jmattson@google.com>
Subject: [PATCH v2 05/21] KVM: x86/mmu: Try to avoid crashing KVM if a MMU memory cache is empty
Date: Mon, 22 Jun 2020 13:08:06 -0700 [thread overview]
Message-ID: <20200622200822.4426-6-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200622200822.4426-1-sean.j.christopherson@intel.com>
Attempt to allocate a new object instead of crashing KVM (and likely the
kernel) if a memory cache is unexpectedly empty. Use GFP_ATOMIC for the
allocation as the caches are used while holding mmu_lock. The immediate
BUG_ON() makes the code unnecessarily explosive and led to confusing
minimums being used in the past, e.g. allocating 4 objects where 1 would
suffice.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ba70de24a5b0..5e773564ab20 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1060,6 +1060,15 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
local_irq_enable();
}
+static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
+ gfp_t gfp_flags)
+{
+ if (mc->kmem_cache)
+ return kmem_cache_zalloc(mc->kmem_cache, gfp_flags);
+ else
+ return (void *)__get_free_page(gfp_flags);
+}
+
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
{
void *obj;
@@ -1067,10 +1076,7 @@ static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
if (mc->nobjs >= min)
return 0;
while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
- if (mc->kmem_cache)
- obj = kmem_cache_zalloc(mc->kmem_cache, GFP_KERNEL_ACCOUNT);
- else
- obj = (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
+ obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
if (!obj)
return mc->nobjs >= min ? 0 : -ENOMEM;
mc->objects[mc->nobjs++] = obj;
@@ -1118,8 +1124,11 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
void *p;
- BUG_ON(!mc->nobjs);
- p = mc->objects[--mc->nobjs];
+ if (WARN_ON(!mc->nobjs))
+ p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
+ else
+ p = mc->objects[--mc->nobjs];
+ BUG_ON(!p);
return p;
}
--
2.26.0
WARNING: multiple messages have this Message-ID (diff)
From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Marc Zyngier <maz@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Arnd Bergmann <arnd@arndb.de>
Cc: James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org,
kvm@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org, Ben Gardon <bgardon@google.com>,
Peter Feiner <pfeiner@google.com>,
Peter Shier <pshier@google.com>,
Junaid Shahid <junaids@google.com>,
Christoffer Dall <christoffer.dall@arm.com>
Subject: [PATCH v2 05/21] KVM: x86/mmu: Try to avoid crashing KVM if a MMU memory cache is empty
Date: Mon, 22 Jun 2020 13:08:06 -0700 [thread overview]
Message-ID: <20200622200822.4426-6-sean.j.christopherson@intel.com> (raw)
Message-ID: <20200622200806.NsVAHNwRUJXbMC8bP0sP0pzlpved2cqo1GBlRwHRxRM@z> (raw)
In-Reply-To: <20200622200822.4426-1-sean.j.christopherson@intel.com>
Attempt to allocate a new object instead of crashing KVM (and likely the
kernel) if a memory cache is unexpectedly empty. Use GFP_ATOMIC for the
allocation as the caches are used while holding mmu_lock. The immediate
BUG_ON() makes the code unnecessarily explosive and led to confusing
minimums being used in the past, e.g. allocating 4 objects where 1 would
suffice.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ba70de24a5b0..5e773564ab20 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1060,6 +1060,15 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
local_irq_enable();
}
+static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
+ gfp_t gfp_flags)
+{
+ if (mc->kmem_cache)
+ return kmem_cache_zalloc(mc->kmem_cache, gfp_flags);
+ else
+ return (void *)__get_free_page(gfp_flags);
+}
+
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
{
void *obj;
@@ -1067,10 +1076,7 @@ static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
if (mc->nobjs >= min)
return 0;
while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
- if (mc->kmem_cache)
- obj = kmem_cache_zalloc(mc->kmem_cache, GFP_KERNEL_ACCOUNT);
- else
- obj = (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
+ obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
if (!obj)
return mc->nobjs >= min ? 0 : -ENOMEM;
mc->objects[mc->nobjs++] = obj;
@@ -1118,8 +1124,11 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
void *p;
- BUG_ON(!mc->nobjs);
- p = mc->objects[--mc->nobjs];
+ if (WARN_ON(!mc->nobjs))
+ p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
+ else
+ p = mc->objects[--mc->nobjs];
+ BUG_ON(!p);
return p;
}
--
2.26.0
next prev parent reply other threads:[~2020-06-22 20:09 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-22 20:08 [PATCH v2 00/21] KVM: Cleanup and unify kvm_mmu_memory_cache usage Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 01/21] KVM: x86/mmu: Track the associated kmem_cache in the MMU caches Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 02/21] KVM: x86/mmu: Consolidate "page" variant of memory cache helpers Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 03/21] KVM: x86/mmu: Use consistent "mc" name for kvm_mmu_memory_cache locals Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 04/21] KVM: x86/mmu: Remove superfluous gotos from mmu_topup_memory_caches() Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson [this message]
2020-06-22 20:08 ` [PATCH v2 05/21] KVM: x86/mmu: Try to avoid crashing KVM if a MMU memory cache is empty Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-24 18:03 ` Ben Gardon
2020-06-24 18:03 ` Ben Gardon
2020-06-24 18:03 ` Ben Gardon
2020-06-22 20:08 ` [PATCH v2 06/21] KVM: x86/mmu: Move fast_page_fault() call above mmu_topup_memory_caches() Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 07/21] KVM: x86/mmu: Topup memory caches after walking GVA->GPA Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 08/21] KVM: x86/mmu: Clean up the gorilla math in mmu_topup_memory_caches() Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 09/21] KVM: x86/mmu: Separate the memory caches for shadow pages and gfn arrays Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 10/21] KVM: x86/mmu: Make __GFP_ZERO a property of the memory cache Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 11/21] KVM: x86/mmu: Zero allocate shadow pages (outside of mmu_lock) Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 12/21] KVM: x86/mmu: Skip filling the gfn cache for guaranteed direct MMU topups Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 13/21] KVM: x86/mmu: Prepend "kvm_" to memory cache helpers that will be global Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 14/21] KVM: Move x86's version of struct kvm_mmu_memory_cache to common code Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-24 18:08 ` Ben Gardon
2020-06-24 18:08 ` Ben Gardon
2020-06-24 18:08 ` Ben Gardon
2020-06-22 20:08 ` [PATCH v2 15/21] KVM: Move x86's MMU memory cache helpers to common KVM code Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 16/21] KVM: arm64: Drop @max param from mmu_topup_memory_cache() Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 17/21] KVM: arm64: Use common code's approach for __GFP_ZERO with memory caches Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 18/21] KVM: arm64: Use common KVM implementation of MMU " Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 19/21] KVM: MIPS: Drop @max param from mmu_topup_memory_cache() Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 20/21] KVM: MIPS: Account pages used for GPA page tables Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-22 20:08 ` [PATCH v2 21/21] KVM: MIPS: Use common KVM implementation of MMU memory caches Sean Christopherson
2020-06-22 20:08 ` Sean Christopherson
2020-06-23 17:26 ` [PATCH v2 00/21] KVM: Cleanup and unify kvm_mmu_memory_cache usage Sean Christopherson
2020-06-23 17:26 ` Sean Christopherson
2020-06-23 17:26 ` Sean Christopherson
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