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 c17af96554a8a8777cbb0fd53b8497250e548b43 Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba(a)suse.com>
Date: Wed, 19 Feb 2020 15:17:20 +0100
Subject: [PATCH] btrfs: raid56: simplify tracking of Q stripe presence
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
There are temporary variables tracking the index of P and Q stripes, but
none of them is really used as such, merely for determining if the Q
stripe is present. This leads to compiler warnings with
-Wunused-but-set-variable and has been reported several times.
fs/btrfs/raid56.c: In function ‘finish_rmw’:
fs/btrfs/raid56.c:1199:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable]
1199 | int p_stripe = -1;
| ^~~~~~~~
fs/btrfs/raid56.c: In function ‘finish_parity_scrub’:
fs/btrfs/raid56.c:2356:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable]
2356 | int p_stripe = -1;
| ^~~~~~~~
Replace the two variables with one that has a clear meaning and also get
rid of the warnings. The logic that verifies that there are only 2
valid cases is unchanged.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn(a)wdc.com>
Signed-off-by: David Sterba <dsterba(a)suse.com>
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index a8e53c8e7b01..406b1efd3ba5 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1196,22 +1196,19 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
int nr_data = rbio->nr_data;
int stripe;
int pagenr;
- int p_stripe = -1;
- int q_stripe = -1;
+ bool has_qstripe;
struct bio_list bio_list;
struct bio *bio;
int ret;
bio_list_init(&bio_list);
- if (rbio->real_stripes - rbio->nr_data == 1) {
- p_stripe = rbio->real_stripes - 1;
- } else if (rbio->real_stripes - rbio->nr_data == 2) {
- p_stripe = rbio->real_stripes - 2;
- q_stripe = rbio->real_stripes - 1;
- } else {
+ if (rbio->real_stripes - rbio->nr_data == 1)
+ has_qstripe = false;
+ else if (rbio->real_stripes - rbio->nr_data == 2)
+ has_qstripe = true;
+ else
BUG();
- }
/* at this point we either have a full stripe,
* or we've read the full stripe from the drive.
@@ -1255,7 +1252,7 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
SetPageUptodate(p);
pointers[stripe++] = kmap(p);
- if (q_stripe != -1) {
+ if (has_qstripe) {
/*
* raid6, add the qstripe and call the
@@ -2353,8 +2350,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
int nr_data = rbio->nr_data;
int stripe;
int pagenr;
- int p_stripe = -1;
- int q_stripe = -1;
+ bool has_qstripe;
struct page *p_page = NULL;
struct page *q_page = NULL;
struct bio_list bio_list;
@@ -2364,14 +2360,12 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
bio_list_init(&bio_list);
- if (rbio->real_stripes - rbio->nr_data == 1) {
- p_stripe = rbio->real_stripes - 1;
- } else if (rbio->real_stripes - rbio->nr_data == 2) {
- p_stripe = rbio->real_stripes - 2;
- q_stripe = rbio->real_stripes - 1;
- } else {
+ if (rbio->real_stripes - rbio->nr_data == 1)
+ has_qstripe = false;
+ else if (rbio->real_stripes - rbio->nr_data == 2)
+ has_qstripe = true;
+ else
BUG();
- }
if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
is_replace = 1;
@@ -2393,7 +2387,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
goto cleanup;
SetPageUptodate(p_page);
- if (q_stripe != -1) {
+ if (has_qstripe) {
q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
if (!q_page) {
__free_page(p_page);
@@ -2416,8 +2410,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
/* then add the parity stripe */
pointers[stripe++] = kmap(p_page);
- if (q_stripe != -1) {
-
+ if (has_qstripe) {
/*
* raid6, add the qstripe and call the
* library function to fill in our p/q
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 44ac5958a6c1fd91ac8810fbb37194e377d78db5 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc(a)google.com>
Date: Thu, 25 Feb 2021 12:47:26 -0800
Subject: [PATCH] KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML
is enabled
Check that PML is actually enabled before setting the mask to force a
SPTE to be write-protected. The bits used for the !AD_ENABLED case are
in the upper half of the SPTE. With 64-bit paging and EPT, these bits
are ignored, but with 32-bit PAE paging they are reserved. Setting them
for L2 SPTEs without checking PML breaks NPT on 32-bit KVM.
Fixes: 1f4e5fc83a42 ("KVM: x86: fix nested guest live migration with PML")
Cc: stable(a)vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc(a)google.com>
Message-Id: <20210225204749.1512652-2-seanjc(a)google.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 72b0928f2b2d..ec4fc28b325a 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -81,15 +81,15 @@ static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
static inline bool kvm_vcpu_ad_need_write_protect(struct kvm_vcpu *vcpu)
{
/*
- * When using the EPT page-modification log, the GPAs in the log
- * would come from L2 rather than L1. Therefore, we need to rely
- * on write protection to record dirty pages. This also bypasses
- * PML, since writes now result in a vmexit. Note, this helper will
- * tag SPTEs as needing write-protection even if PML is disabled or
- * unsupported, but that's ok because the tag is consumed if and only
- * if PML is enabled. Omit the PML check to save a few uops.
+ * When using the EPT page-modification log, the GPAs in the CPU dirty
+ * log would come from L2 rather than L1. Therefore, we need to rely
+ * on write protection to record dirty pages, which bypasses PML, since
+ * writes now result in a vmexit. Note, the check on CPU dirty logging
+ * being enabled is mandatory as the bits used to denote WP-only SPTEs
+ * are reserved for NPT w/ PAE (32-bit KVM).
*/
- return vcpu->arch.mmu == &vcpu->arch.guest_mmu;
+ return vcpu->arch.mmu == &vcpu->arch.guest_mmu &&
+ kvm_x86_ops.cpu_dirty_log_size;
}
bool is_nx_huge_page_enabled(void);
The patch below does not apply to the 5.11-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 44ac5958a6c1fd91ac8810fbb37194e377d78db5 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc(a)google.com>
Date: Thu, 25 Feb 2021 12:47:26 -0800
Subject: [PATCH] KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML
is enabled
Check that PML is actually enabled before setting the mask to force a
SPTE to be write-protected. The bits used for the !AD_ENABLED case are
in the upper half of the SPTE. With 64-bit paging and EPT, these bits
are ignored, but with 32-bit PAE paging they are reserved. Setting them
for L2 SPTEs without checking PML breaks NPT on 32-bit KVM.
Fixes: 1f4e5fc83a42 ("KVM: x86: fix nested guest live migration with PML")
Cc: stable(a)vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc(a)google.com>
Message-Id: <20210225204749.1512652-2-seanjc(a)google.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 72b0928f2b2d..ec4fc28b325a 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -81,15 +81,15 @@ static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
static inline bool kvm_vcpu_ad_need_write_protect(struct kvm_vcpu *vcpu)
{
/*
- * When using the EPT page-modification log, the GPAs in the log
- * would come from L2 rather than L1. Therefore, we need to rely
- * on write protection to record dirty pages. This also bypasses
- * PML, since writes now result in a vmexit. Note, this helper will
- * tag SPTEs as needing write-protection even if PML is disabled or
- * unsupported, but that's ok because the tag is consumed if and only
- * if PML is enabled. Omit the PML check to save a few uops.
+ * When using the EPT page-modification log, the GPAs in the CPU dirty
+ * log would come from L2 rather than L1. Therefore, we need to rely
+ * on write protection to record dirty pages, which bypasses PML, since
+ * writes now result in a vmexit. Note, the check on CPU dirty logging
+ * being enabled is mandatory as the bits used to denote WP-only SPTEs
+ * are reserved for NPT w/ PAE (32-bit KVM).
*/
- return vcpu->arch.mmu == &vcpu->arch.guest_mmu;
+ return vcpu->arch.mmu == &vcpu->arch.guest_mmu &&
+ kvm_x86_ops.cpu_dirty_log_size;
}
bool is_nx_huge_page_enabled(void);
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 44ac5958a6c1fd91ac8810fbb37194e377d78db5 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc(a)google.com>
Date: Thu, 25 Feb 2021 12:47:26 -0800
Subject: [PATCH] KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML
is enabled
Check that PML is actually enabled before setting the mask to force a
SPTE to be write-protected. The bits used for the !AD_ENABLED case are
in the upper half of the SPTE. With 64-bit paging and EPT, these bits
are ignored, but with 32-bit PAE paging they are reserved. Setting them
for L2 SPTEs without checking PML breaks NPT on 32-bit KVM.
Fixes: 1f4e5fc83a42 ("KVM: x86: fix nested guest live migration with PML")
Cc: stable(a)vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc(a)google.com>
Message-Id: <20210225204749.1512652-2-seanjc(a)google.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 72b0928f2b2d..ec4fc28b325a 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -81,15 +81,15 @@ static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
static inline bool kvm_vcpu_ad_need_write_protect(struct kvm_vcpu *vcpu)
{
/*
- * When using the EPT page-modification log, the GPAs in the log
- * would come from L2 rather than L1. Therefore, we need to rely
- * on write protection to record dirty pages. This also bypasses
- * PML, since writes now result in a vmexit. Note, this helper will
- * tag SPTEs as needing write-protection even if PML is disabled or
- * unsupported, but that's ok because the tag is consumed if and only
- * if PML is enabled. Omit the PML check to save a few uops.
+ * When using the EPT page-modification log, the GPAs in the CPU dirty
+ * log would come from L2 rather than L1. Therefore, we need to rely
+ * on write protection to record dirty pages, which bypasses PML, since
+ * writes now result in a vmexit. Note, the check on CPU dirty logging
+ * being enabled is mandatory as the bits used to denote WP-only SPTEs
+ * are reserved for NPT w/ PAE (32-bit KVM).
*/
- return vcpu->arch.mmu == &vcpu->arch.guest_mmu;
+ return vcpu->arch.mmu == &vcpu->arch.guest_mmu &&
+ kvm_x86_ops.cpu_dirty_log_size;
}
bool is_nx_huge_page_enabled(void);