The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 7131636e7ea5b50ca910f8953f6365ef2d1f741c Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini(a)redhat.com>
Date: Thu, 28 Jan 2021 11:45:00 -0500
Subject: [PATCH] KVM: x86: Allow guests to see MSR_IA32_TSX_CTRL even if
tsx=off
Userspace that does not know about KVM_GET_MSR_FEATURE_INDEX_LIST
will generally use the default value for MSR_IA32_ARCH_CAPABILITIES.
When this happens and the host has tsx=on, it is possible to end up with
virtual machines that have HLE and RTM disabled, but TSX_CTRL available.
If the fleet is then switched to tsx=off, kvm_get_arch_capabilities()
will clear the ARCH_CAP_TSX_CTRL_MSR bit and it will not be possible to
use the tsx=off hosts as migration destinations, even though the guests
do not have TSX enabled.
To allow this migration, allow guests to write to their TSX_CTRL MSR,
while keeping the host MSR unchanged for the entire life of the guests.
This ensures that TSX remains disabled and also saves MSR reads and
writes, and it's okay to do because with tsx=off we know that guests will
not have the HLE and RTM features in their CPUID. (If userspace sets
bogus CPUID data, we do not expect HLE and RTM to work in guests anyway).
Cc: stable(a)vger.kernel.org
Fixes: cbbaa2727aa3 ("KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES")
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index cc60b1fc3ee7..eb69fef57485 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6860,11 +6860,20 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
switch (index) {
case MSR_IA32_TSX_CTRL:
/*
- * No need to pass TSX_CTRL_CPUID_CLEAR through, so
- * let's avoid changing CPUID bits under the host
- * kernel's feet.
+ * TSX_CTRL_CPUID_CLEAR is handled in the CPUID
+ * interception. Keep the host value unchanged to avoid
+ * changing CPUID bits under the host kernel's feet.
+ *
+ * hle=0, rtm=0, tsx_ctrl=1 can be found with some
+ * combinations of new kernel and old userspace. If
+ * those guests run on a tsx=off host, do allow guests
+ * to use TSX_CTRL, but do not change the value on the
+ * host so that TSX remains always disabled.
*/
- vmx->guest_uret_msrs[j].mask = ~(u64)TSX_CTRL_CPUID_CLEAR;
+ if (boot_cpu_has(X86_FEATURE_RTM))
+ vmx->guest_uret_msrs[j].mask = ~(u64)TSX_CTRL_CPUID_CLEAR;
+ else
+ vmx->guest_uret_msrs[j].mask = 0;
break;
default:
vmx->guest_uret_msrs[j].mask = -1ull;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76bce832cade..b05a1fe9dae9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1394,16 +1394,24 @@ static u64 kvm_get_arch_capabilities(void)
if (!boot_cpu_has_bug(X86_BUG_MDS))
data |= ARCH_CAP_MDS_NO;
- /*
- * On TAA affected systems:
- * - nothing to do if TSX is disabled on the host.
- * - we emulate TSX_CTRL if present on the host.
- * This lets the guest use VERW to clear CPU buffers.
- */
- if (!boot_cpu_has(X86_FEATURE_RTM))
- data &= ~(ARCH_CAP_TAA_NO | ARCH_CAP_TSX_CTRL_MSR);
- else if (!boot_cpu_has_bug(X86_BUG_TAA))
+ if (!boot_cpu_has(X86_FEATURE_RTM)) {
+ /*
+ * If RTM=0 because the kernel has disabled TSX, the host might
+ * have TAA_NO or TSX_CTRL. Clear TAA_NO (the guest sees RTM=0
+ * and therefore knows that there cannot be TAA) but keep
+ * TSX_CTRL: some buggy userspaces leave it set on tsx=on hosts,
+ * and we want to allow migrating those guests to tsx=off hosts.
+ */
+ data &= ~ARCH_CAP_TAA_NO;
+ } else if (!boot_cpu_has_bug(X86_BUG_TAA)) {
data |= ARCH_CAP_TAA_NO;
+ } else {
+ /*
+ * Nothing to do here; we emulate TSX_CTRL if present on the
+ * host so the guest can choose between disabling TSX or
+ * using VERW to clear CPU buffers.
+ */
+ }
return data;
}
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 7131636e7ea5b50ca910f8953f6365ef2d1f741c Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini(a)redhat.com>
Date: Thu, 28 Jan 2021 11:45:00 -0500
Subject: [PATCH] KVM: x86: Allow guests to see MSR_IA32_TSX_CTRL even if
tsx=off
Userspace that does not know about KVM_GET_MSR_FEATURE_INDEX_LIST
will generally use the default value for MSR_IA32_ARCH_CAPABILITIES.
When this happens and the host has tsx=on, it is possible to end up with
virtual machines that have HLE and RTM disabled, but TSX_CTRL available.
If the fleet is then switched to tsx=off, kvm_get_arch_capabilities()
will clear the ARCH_CAP_TSX_CTRL_MSR bit and it will not be possible to
use the tsx=off hosts as migration destinations, even though the guests
do not have TSX enabled.
To allow this migration, allow guests to write to their TSX_CTRL MSR,
while keeping the host MSR unchanged for the entire life of the guests.
This ensures that TSX remains disabled and also saves MSR reads and
writes, and it's okay to do because with tsx=off we know that guests will
not have the HLE and RTM features in their CPUID. (If userspace sets
bogus CPUID data, we do not expect HLE and RTM to work in guests anyway).
Cc: stable(a)vger.kernel.org
Fixes: cbbaa2727aa3 ("KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES")
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index cc60b1fc3ee7..eb69fef57485 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6860,11 +6860,20 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
switch (index) {
case MSR_IA32_TSX_CTRL:
/*
- * No need to pass TSX_CTRL_CPUID_CLEAR through, so
- * let's avoid changing CPUID bits under the host
- * kernel's feet.
+ * TSX_CTRL_CPUID_CLEAR is handled in the CPUID
+ * interception. Keep the host value unchanged to avoid
+ * changing CPUID bits under the host kernel's feet.
+ *
+ * hle=0, rtm=0, tsx_ctrl=1 can be found with some
+ * combinations of new kernel and old userspace. If
+ * those guests run on a tsx=off host, do allow guests
+ * to use TSX_CTRL, but do not change the value on the
+ * host so that TSX remains always disabled.
*/
- vmx->guest_uret_msrs[j].mask = ~(u64)TSX_CTRL_CPUID_CLEAR;
+ if (boot_cpu_has(X86_FEATURE_RTM))
+ vmx->guest_uret_msrs[j].mask = ~(u64)TSX_CTRL_CPUID_CLEAR;
+ else
+ vmx->guest_uret_msrs[j].mask = 0;
break;
default:
vmx->guest_uret_msrs[j].mask = -1ull;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76bce832cade..b05a1fe9dae9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1394,16 +1394,24 @@ static u64 kvm_get_arch_capabilities(void)
if (!boot_cpu_has_bug(X86_BUG_MDS))
data |= ARCH_CAP_MDS_NO;
- /*
- * On TAA affected systems:
- * - nothing to do if TSX is disabled on the host.
- * - we emulate TSX_CTRL if present on the host.
- * This lets the guest use VERW to clear CPU buffers.
- */
- if (!boot_cpu_has(X86_FEATURE_RTM))
- data &= ~(ARCH_CAP_TAA_NO | ARCH_CAP_TSX_CTRL_MSR);
- else if (!boot_cpu_has_bug(X86_BUG_TAA))
+ if (!boot_cpu_has(X86_FEATURE_RTM)) {
+ /*
+ * If RTM=0 because the kernel has disabled TSX, the host might
+ * have TAA_NO or TSX_CTRL. Clear TAA_NO (the guest sees RTM=0
+ * and therefore knows that there cannot be TAA) but keep
+ * TSX_CTRL: some buggy userspaces leave it set on tsx=on hosts,
+ * and we want to allow migrating those guests to tsx=off hosts.
+ */
+ data &= ~ARCH_CAP_TAA_NO;
+ } else if (!boot_cpu_has_bug(X86_BUG_TAA)) {
data |= ARCH_CAP_TAA_NO;
+ } else {
+ /*
+ * Nothing to do here; we emulate TSX_CTRL if present on the
+ * host so the guest can choose between disabling TSX or
+ * using VERW to clear CPU buffers.
+ */
+ }
return data;
}
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 7131636e7ea5b50ca910f8953f6365ef2d1f741c Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini(a)redhat.com>
Date: Thu, 28 Jan 2021 11:45:00 -0500
Subject: [PATCH] KVM: x86: Allow guests to see MSR_IA32_TSX_CTRL even if
tsx=off
Userspace that does not know about KVM_GET_MSR_FEATURE_INDEX_LIST
will generally use the default value for MSR_IA32_ARCH_CAPABILITIES.
When this happens and the host has tsx=on, it is possible to end up with
virtual machines that have HLE and RTM disabled, but TSX_CTRL available.
If the fleet is then switched to tsx=off, kvm_get_arch_capabilities()
will clear the ARCH_CAP_TSX_CTRL_MSR bit and it will not be possible to
use the tsx=off hosts as migration destinations, even though the guests
do not have TSX enabled.
To allow this migration, allow guests to write to their TSX_CTRL MSR,
while keeping the host MSR unchanged for the entire life of the guests.
This ensures that TSX remains disabled and also saves MSR reads and
writes, and it's okay to do because with tsx=off we know that guests will
not have the HLE and RTM features in their CPUID. (If userspace sets
bogus CPUID data, we do not expect HLE and RTM to work in guests anyway).
Cc: stable(a)vger.kernel.org
Fixes: cbbaa2727aa3 ("KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES")
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index cc60b1fc3ee7..eb69fef57485 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6860,11 +6860,20 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
switch (index) {
case MSR_IA32_TSX_CTRL:
/*
- * No need to pass TSX_CTRL_CPUID_CLEAR through, so
- * let's avoid changing CPUID bits under the host
- * kernel's feet.
+ * TSX_CTRL_CPUID_CLEAR is handled in the CPUID
+ * interception. Keep the host value unchanged to avoid
+ * changing CPUID bits under the host kernel's feet.
+ *
+ * hle=0, rtm=0, tsx_ctrl=1 can be found with some
+ * combinations of new kernel and old userspace. If
+ * those guests run on a tsx=off host, do allow guests
+ * to use TSX_CTRL, but do not change the value on the
+ * host so that TSX remains always disabled.
*/
- vmx->guest_uret_msrs[j].mask = ~(u64)TSX_CTRL_CPUID_CLEAR;
+ if (boot_cpu_has(X86_FEATURE_RTM))
+ vmx->guest_uret_msrs[j].mask = ~(u64)TSX_CTRL_CPUID_CLEAR;
+ else
+ vmx->guest_uret_msrs[j].mask = 0;
break;
default:
vmx->guest_uret_msrs[j].mask = -1ull;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76bce832cade..b05a1fe9dae9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1394,16 +1394,24 @@ static u64 kvm_get_arch_capabilities(void)
if (!boot_cpu_has_bug(X86_BUG_MDS))
data |= ARCH_CAP_MDS_NO;
- /*
- * On TAA affected systems:
- * - nothing to do if TSX is disabled on the host.
- * - we emulate TSX_CTRL if present on the host.
- * This lets the guest use VERW to clear CPU buffers.
- */
- if (!boot_cpu_has(X86_FEATURE_RTM))
- data &= ~(ARCH_CAP_TAA_NO | ARCH_CAP_TSX_CTRL_MSR);
- else if (!boot_cpu_has_bug(X86_BUG_TAA))
+ if (!boot_cpu_has(X86_FEATURE_RTM)) {
+ /*
+ * If RTM=0 because the kernel has disabled TSX, the host might
+ * have TAA_NO or TSX_CTRL. Clear TAA_NO (the guest sees RTM=0
+ * and therefore knows that there cannot be TAA) but keep
+ * TSX_CTRL: some buggy userspaces leave it set on tsx=on hosts,
+ * and we want to allow migrating those guests to tsx=off hosts.
+ */
+ data &= ~ARCH_CAP_TAA_NO;
+ } else if (!boot_cpu_has_bug(X86_BUG_TAA)) {
data |= ARCH_CAP_TAA_NO;
+ } else {
+ /*
+ * Nothing to do here; we emulate TSX_CTRL if present on the
+ * host so the guest can choose between disabling TSX or
+ * using VERW to clear CPU buffers.
+ */
+ }
return data;
}
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From aec18a57edad562d620f7d19016de1fc0cc2208c Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence(a)gmail.com>
Date: Thu, 4 Feb 2021 19:22:46 +0000
Subject: [PATCH] io_uring: drop mm/files between task_work_submit
Since SQPOLL task can be shared and so task_work entries can be a mix of
them, we need to drop mm and files before trying to issue next request.
Cc: stable(a)vger.kernel.org # 5.10+
Signed-off-by: Pavel Begunkov <asml.silence(a)gmail.com>
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5d3348d66f06..1f68105a41ed 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2205,6 +2205,9 @@ static void __io_req_task_submit(struct io_kiocb *req)
else
__io_req_task_cancel(req, -EFAULT);
mutex_unlock(&ctx->uring_lock);
+
+ if (ctx->flags & IORING_SETUP_SQPOLL)
+ io_sq_thread_drop_mm_files();
}
static void io_req_task_submit(struct callback_head *cb)
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 89fa15ecdca7eb46a711476b961f70a74765bbe4 Mon Sep 17 00:00:00 2001
From: Huang Rui <ray.huang(a)amd.com>
Date: Sat, 30 Jan 2021 17:14:30 +0800
Subject: [PATCH] drm/amdgpu: fix the issue that retry constantly once the
buffer is oversize
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
We cannot modify initial_domain every time while the retry starts. That
will cause the busy waiting that unable to switch to GTT while the vram
is not enough.
Fixes: f8aab60422c3 ("drm/amdgpu: Initialise drm_gem_object_funcs for imported BOs")
Signed-off-by: Huang Rui <ray.huang(a)amd.com>
Reviewed-by: Alex Deucher <alexander.deucher(a)amd.com>
Reviewed-by: Christian König <christian.koenig(a)amd.com>
Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com>
Cc: stable(a)vger.kernel.org
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index d0a1fee1f5f6..174a73eb23f0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -269,8 +269,8 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
resv = vm->root.base.bo->tbo.base.resv;
}
-retry:
initial_domain = (u32)(0xffffffff & args->in.domains);
+retry:
r = amdgpu_gem_object_create(adev, size, args->in.alignment,
initial_domain,
flags, ttm_bo_type_device, resv, &gobj);
The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 19a23da53932bc8011220bd8c410cb76012de004 Mon Sep 17 00:00:00 2001
From: Peter Gonda <pgonda(a)google.com>
Date: Wed, 27 Jan 2021 08:15:24 -0800
Subject: [PATCH] Fix unsynchronized access to sev members through
svm_register_enc_region
Grab kvm->lock before pinning memory when registering an encrypted
region; sev_pin_memory() relies on kvm->lock being held to ensure
correctness when checking and updating the number of pinned pages.
Add a lockdep assertion to help prevent future regressions.
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: "H. Peter Anvin" <hpa(a)zytor.com>
Cc: Paolo Bonzini <pbonzini(a)redhat.com>
Cc: Joerg Roedel <joro(a)8bytes.org>
Cc: Tom Lendacky <thomas.lendacky(a)amd.com>
Cc: Brijesh Singh <brijesh.singh(a)amd.com>
Cc: Sean Christopherson <seanjc(a)google.com>
Cc: x86(a)kernel.org
Cc: kvm(a)vger.kernel.org
Cc: stable(a)vger.kernel.org
Cc: linux-kernel(a)vger.kernel.org
Fixes: 1e80fdc09d12 ("KVM: SVM: Pin guest memory when SEV is active")
Signed-off-by: Peter Gonda <pgonda(a)google.com>
V2
- Fix up patch description
- Correct file paths svm.c -> sev.c
- Add unlock of kvm->lock on sev_pin_memory error
V1
- https://lore.kernel.org/kvm/20210126185431.1824530-1-pgonda@google.com/
Message-Id: <20210127161524.2832400-1-pgonda(a)google.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index ac652bc476ae..48017fef1cd9 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -342,6 +342,8 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
unsigned long first, last;
int ret;
+ lockdep_assert_held(&kvm->lock);
+
if (ulen == 0 || uaddr + ulen < uaddr)
return ERR_PTR(-EINVAL);
@@ -1119,12 +1121,20 @@ int svm_register_enc_region(struct kvm *kvm,
if (!region)
return -ENOMEM;
+ mutex_lock(&kvm->lock);
region->pages = sev_pin_memory(kvm, range->addr, range->size, ®ion->npages, 1);
if (IS_ERR(region->pages)) {
ret = PTR_ERR(region->pages);
+ mutex_unlock(&kvm->lock);
goto e_free;
}
+ region->uaddr = range->addr;
+ region->size = range->size;
+
+ list_add_tail(®ion->list, &sev->regions_list);
+ mutex_unlock(&kvm->lock);
+
/*
* The guest may change the memory encryption attribute from C=0 -> C=1
* or vice versa for this memory range. Lets make sure caches are
@@ -1133,13 +1143,6 @@ int svm_register_enc_region(struct kvm *kvm,
*/
sev_clflush_pages(region->pages, region->npages);
- region->uaddr = range->addr;
- region->size = range->size;
-
- mutex_lock(&kvm->lock);
- list_add_tail(®ion->list, &sev->regions_list);
- mutex_unlock(&kvm->lock);
-
return ret;
e_free:
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 19a23da53932bc8011220bd8c410cb76012de004 Mon Sep 17 00:00:00 2001
From: Peter Gonda <pgonda(a)google.com>
Date: Wed, 27 Jan 2021 08:15:24 -0800
Subject: [PATCH] Fix unsynchronized access to sev members through
svm_register_enc_region
Grab kvm->lock before pinning memory when registering an encrypted
region; sev_pin_memory() relies on kvm->lock being held to ensure
correctness when checking and updating the number of pinned pages.
Add a lockdep assertion to help prevent future regressions.
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: "H. Peter Anvin" <hpa(a)zytor.com>
Cc: Paolo Bonzini <pbonzini(a)redhat.com>
Cc: Joerg Roedel <joro(a)8bytes.org>
Cc: Tom Lendacky <thomas.lendacky(a)amd.com>
Cc: Brijesh Singh <brijesh.singh(a)amd.com>
Cc: Sean Christopherson <seanjc(a)google.com>
Cc: x86(a)kernel.org
Cc: kvm(a)vger.kernel.org
Cc: stable(a)vger.kernel.org
Cc: linux-kernel(a)vger.kernel.org
Fixes: 1e80fdc09d12 ("KVM: SVM: Pin guest memory when SEV is active")
Signed-off-by: Peter Gonda <pgonda(a)google.com>
V2
- Fix up patch description
- Correct file paths svm.c -> sev.c
- Add unlock of kvm->lock on sev_pin_memory error
V1
- https://lore.kernel.org/kvm/20210126185431.1824530-1-pgonda@google.com/
Message-Id: <20210127161524.2832400-1-pgonda(a)google.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index ac652bc476ae..48017fef1cd9 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -342,6 +342,8 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
unsigned long first, last;
int ret;
+ lockdep_assert_held(&kvm->lock);
+
if (ulen == 0 || uaddr + ulen < uaddr)
return ERR_PTR(-EINVAL);
@@ -1119,12 +1121,20 @@ int svm_register_enc_region(struct kvm *kvm,
if (!region)
return -ENOMEM;
+ mutex_lock(&kvm->lock);
region->pages = sev_pin_memory(kvm, range->addr, range->size, ®ion->npages, 1);
if (IS_ERR(region->pages)) {
ret = PTR_ERR(region->pages);
+ mutex_unlock(&kvm->lock);
goto e_free;
}
+ region->uaddr = range->addr;
+ region->size = range->size;
+
+ list_add_tail(®ion->list, &sev->regions_list);
+ mutex_unlock(&kvm->lock);
+
/*
* The guest may change the memory encryption attribute from C=0 -> C=1
* or vice versa for this memory range. Lets make sure caches are
@@ -1133,13 +1143,6 @@ int svm_register_enc_region(struct kvm *kvm,
*/
sev_clflush_pages(region->pages, region->npages);
- region->uaddr = range->addr;
- region->size = range->size;
-
- mutex_lock(&kvm->lock);
- list_add_tail(®ion->list, &sev->regions_list);
- mutex_unlock(&kvm->lock);
-
return ret;
e_free:
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 7018c897c2f243d4b5f1b94bc6b4831a7eab80fb Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams(a)intel.com>
Date: Mon, 1 Feb 2021 16:20:40 -0800
Subject: [PATCH] libnvdimm/dimm: Avoid race between probe and
available_slots_show()
Richard reports that the following test:
(while true; do
cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null
done) &
while true; do
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind
done
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind
done
done
...fails with a crash signature like:
divide error: 0000 [#1] SMP KASAN PTI
RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
[..]
Call Trace:
available_slots_show+0x4e/0x120 [libnvdimm]
dev_attr_show+0x42/0x80
? memset+0x20/0x40
sysfs_kf_seq_show+0x218/0x410
The root cause is that available_slots_show() consults driver-data, but
fails to synchronize against device-unbind setting up a TOCTOU race to
access uninitialized memory.
Validate driver-data under the device-lock.
Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver infrastructure")
Cc: <stable(a)vger.kernel.org>
Cc: Vishal Verma <vishal.l.verma(a)intel.com>
Cc: Dave Jiang <dave.jiang(a)intel.com>
Cc: Ira Weiny <ira.weiny(a)intel.com>
Cc: Coly Li <colyli(a)suse.com>
Reported-by: Richard Palethorpe <rpalethorpe(a)suse.com>
Acked-by: Richard Palethorpe <rpalethorpe(a)suse.com>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index b59032e0859b..9d208570d059 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -335,16 +335,16 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(state);
-static ssize_t available_slots_show(struct device *dev,
- struct device_attribute *attr, char *buf)
+static ssize_t __available_slots_show(struct nvdimm_drvdata *ndd, char *buf)
{
- struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);
+ struct device *dev;
ssize_t rc;
u32 nfree;
if (!ndd)
return -ENXIO;
+ dev = ndd->dev;
nvdimm_bus_lock(dev);
nfree = nd_label_nfree(ndd);
if (nfree - 1 > nfree) {
@@ -356,6 +356,18 @@ static ssize_t available_slots_show(struct device *dev,
nvdimm_bus_unlock(dev);
return rc;
}
+
+static ssize_t available_slots_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t rc;
+
+ nd_device_lock(dev);
+ rc = __available_slots_show(dev_get_drvdata(dev), buf);
+ nd_device_unlock(dev);
+
+ return rc;
+}
static DEVICE_ATTR_RO(available_slots);
__weak ssize_t security_show(struct device *dev,