In certain code paths, KVM/ARM currently invalidates the entire VM's
page-tables instead of just invalidating a necessary range. For example,
when collapsing a table PTE to a block PTE, instead of iterating over
each PTE and flushing them, KVM uses 'vmalls12e1is' TLBI operation to
flush all the entries. This is inefficient since the guest would have
to refill the TLBs again, even for the addresses that aren't covered
by the table entry. The performance impact would scale poorly if many
addresses in the VM is going through this remapping.
For architectures that implement FEAT_TLBIRANGE, KVM can replace such
inefficient paths by performing the invalidations only on the range of
addresses that are in scope. This series tries to achieve the same in
the areas of stage-2 map, unmap and write-protecting the pages.
As suggested by Oliver in the original v5 of the series [1], I'm
posting the series by including v2 of David Matlack's 'KVM: Add a
common API for range-based TLB invalidation' series [2].
Patches 1-6 includes David M.'s patches 1, 2, 6, and 7 from [2],
with minor modifications as per upstream comments.
Patch-7 refactors the core arm64's __flush_tlb_range() to be used by
other entities and patch-8 introduces a wrapper over it,
__flush_s2_tlb_range_op(), more suited for stage-2 flushes.
Patch-9,10 adds a range-based TLBI mechanism for KVM (VHE and nVHE).
Patch-11 implements the kvm_arch_flush_remote_tlbs_range() for arm64.
Patch-12 aims to flush only the memslot that undergoes a write-protect,
instead of the entire VM.
Patch-13 operates on stage2_try_break_pte() to use the range based
TLBI instructions when collapsing a table entry. The map path is the
immediate consumer of this when KVM remaps a table entry into a block.
Patch-14 modifies the stage-2 unmap path in which, if the system
supports FEAT_TLBIRANGE, the TLB invalidations are skipped during the
page-table. walk. Instead it's done in one go after the entire walk
is finished.
The series is based off of upstream v6.5-rc1.
The performance evaluation was done on a hardware that supports
FEAT_TLBIRANGE, on a VHE configuration, using a modified
kvm_page_table_test.
The modified version updates the guest code in the ADJUST_MAPPINGS case
to not only access this page but also to access up to 512 pages
backwards for every new page it iterates through. This is done to test
the effect of TLBI misses after KVM has handled a fault.
The series captures the impact in the map and unmap paths as described
above.
$ kvm_page_table_test -m 2 -v 128 -s anonymous_hugetlb_2mb -b $i
+--------+------------------------------+------------------------------+
| mem_sz | ADJUST_MAPPINGS (s) | Unmap VM (s) |
| (GB) | Baseline | Baseline + series | Baseline | Baseline + series |
+--------+----------|-------------------+------------------------------+
| 1 | 3.33 | 3.22 | 0.009 | 0.005 |
| 2 | 7.39 | 7.32 | 0.012 | 0.006 |
| 4 | 13.49 | 10.50 | 0.017 | 0.008 |
| 8 | 21.60 | 21.50 | 0.027 | 0.011 |
| 16 | 57.02 | 43.63 | 0.046 | 0.018 |
| 32 | 95.92 | 83.26 | 0.087 | 0.030 |
| 64 | 199.57 | 165.14 | 0.146 | 0.055 |
| 128 | 423.65 | 349.37 | 0.280 | 0.100 |
+--------+----------+-------------------+----------+-------------------+
$ kvm_page_table_test -m 2 -b 128G -s anonymous_hugetlb_2mb -v $i
+--------+------------------------------+
| vCPUs | ADJUST_MAPPINGS (s) |
| | Baseline | Baseline + series |
+--------+----------|-------------------+
| 1 | 111.44 | 114.63 |
| 2 | 102.88 | 74.64 |
| 4 | 134.83 | 98.78 |
| 8 | 98.81 | 95.01 |
| 16 | 127.41 | 99.05 |
| 32 | 105.35 | 91.75 |
| 64 | 201.13 | 163.63 |
| 128 | 423.65 | 349.37 |
+--------+----------+-------------------+
For the ADJUST_MAPPINGS cases, which maps back the 4K table entries to
2M hugepages, the series sees an average improvement of ~15%. For
unmapping 2M hugepages, we see a gain of 2x to 3x.
$ kvm_page_table_test -m 2 -b $i
+--------+------------------------------+
| mem_sz | Unmap VM (s) |
| (GB) | Baseline | Baseline + series |
+--------+------------------------------+
| 1 | 0.54 | 0.13 |
| 2 | 1.07 | 0.25 |
| 4 | 2.10 | 0.47 |
| 8 | 4.19 | 0.92 |
| 16 | 8.35 | 1.92 |
| 32 | 16.66 | 3.61 |
| 64 | 32.36 | 7.62 |
| 128 | 64.65 | 14.39 |
+--------+----------+-------------------+
The series sees an average gain of 4x when the guest backed by
PAGE_SIZE (4K) pages.
Other testing:
- Booted on x86_64 and ran KVM selftests.
- Build tested for MIPS and RISCV architectures with
malta_kvm_defconfig and defconfig, respectively.
Cc: David Matlack <[email protected]>
v8:
https://lore.kernel.org/all/[email protected]/
- Thanks for the suggestions from Gavin, Sean, and Shaoqin
- Fix the build error reported by the kernel test robot in patch-11/14.
- Fix typo in patch-9/14. (Gavin)
- Renamed 'start_gfn' argument to 'gfn' in patch-5/14. (Gavin)
v7:
https://lore.kernel.org/all/[email protected]/
Thanks, Marc and Sean for the reviews and suggestions
- Made the function declaration for kvm_arch_flush_remote_tlbs() global.
(Marc, Sean)
- Rename 'pages' to 'nr_pages' in TLBI functions that were introduced in
the series. (Sean)
- Define __flush_s2_tlb_range_op() as a wrapper over
__flush_tlb_range_op(). (Marc)
- Correct/improve the comments as suggested throughout the series.
(Marc)
- Get rid of WARN_ON() check and the 'struct stage2_unmap_data' as they
were not necessary. (Marc)
v6:
https://lore.kernel.org/all/[email protected]/
Thank you, Philippe and Shaoqin for the reviews and suggestions
- Split the patch-2/11 to separate the removal of
CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL and arm64 to switch to using
kvm_arch_flush_remote_tlbs(). (Philippe)
- Align the 'pages' argument with 'kvm' in patch-3/11. (Shaoqin)
- Call __tlb_switch_to_guest() before __flush_tlb_range_op()
in the VHE's implementation of __kvm_tlb_flush_vmid_range().
(Shaoqin)
v5 (RESEND):
https://lore.kernel.org/all/[email protected]/
Thanks, Gavin for the suggestions:
- Adjusted the comment on patch-2 to align with the code.
- Fixed checkpatch.pl warning on patch-5.
v5:
https://lore.kernel.org/all/[email protected]/
Thank you, Marc and Oliver for the comments
- Introduced a helper, kvm_tlb_flush_vmid_range(), to handle
the decision of using range-based TLBI instructions or
invalidating the entire VMID, rather than depending on
__kvm_tlb_flush_vmid_range() for it.
- kvm_tlb_flush_vmid_range() splits the range-based invalidations
if the requested range exceeds MAX_TLBI_RANGE_PAGES.
- All the users in need of invalidating the TLB upon a range
now depends on kvm_tlb_flush_vmid_range() rather than directly
on __kvm_tlb_flush_vmid_range().
- stage2_unmap_defer_tlb_flush() introduces a WARN_ON() to
track if there's any change in TLBIRANGE or FWB support
during the unmap process as the features are based on
alternative patching and the TLBI operations solely depend
on this check.
- Corrected an incorrect hunk being present on v4's patch-3.
- Updated the patches changelog and code comments as per the
suggestions.
v4:
https://lore.kernel.org/all/[email protected]/
Thanks again, Oliver for all the comments
- Updated the __kvm_tlb_flush_vmid_range() implementation for
nVHE to adjust with the modified __tlb_switch_to_guest() that
accepts a new 'bool nsh' arg.
- Renamed stage2_put_pte() to stage2_unmap_put_pte() and removed
the 'skip_flush' argument.
- Defined stage2_unmap_defer_tlb_flush() to check if the PTE
flushes can be deferred during the unmap table walk. It's
being called from stage2_unmap_put_pte() and
kvm_pgtable_stage2_unmap().
- Got rid of the 'struct stage2_unmap_data'.
v3:
https://lore.kernel.org/all/[email protected]/
Thanks, Oliver for all the suggestions.
- The core flush API (__kvm_tlb_flush_vmid_range()) now checks if
the system support FEAT_TLBIRANGE or not, thus eliminating the
redundancy in the upper layers.
- If FEAT_TLBIRANGE is not supported, the implementation falls
back to invalidating all the TLB entries with the VMID, instead
of doing an iterative flush for the range.
- The kvm_arch_flush_remote_tlbs_range() doesn't return -EOPNOTSUPP
if the system doesn't implement FEAT_TLBIRANGE. It depends on
__kvm_tlb_flush_vmid_range() to do take care of the decisions
and return 0 regardless of the underlying feature support.
- __kvm_tlb_flush_vmid_range() doesn't take 'level' as input to
calculate the 'stride'. Instead, it always assumes PAGE_SIZE.
- Fast unmap path is eliminated. Instead, the existing unmap walker
is modified to skip the TLBIs during the walk, and do it all at
once after the walk, using the range-based instructions.
v2:
https://lore.kernel.org/all/[email protected]/
- Rebased the series on top of David Matlack's series for common
TLB invalidation API[1].
- Implement kvm_arch_flush_remote_tlbs_range() for arm64, by extending
the support introduced by [1].
- Use kvm_flush_remote_tlbs_memslot() introduced by [1] to flush
only the current memslot after write-protect.
- Modified the __kvm_tlb_flush_range() macro to accepts 'level' as an
argument to calculate the 'stride' instead of just using PAGE_SIZE.
- Split the patch that introduces the range-based TLBI to KVM and the
implementation of IPA-based invalidation into its own patches.
- Dropped the patch that tries to optimize the mmu notifiers paths.
- Rename the function kvm_table_pte_flush() to
kvm_pgtable_stage2_flush_range(), and accept the range of addresses to
flush. [Oliver]
- Drop the 'tlb_level' argument for stage2_try_break_pte() and directly
pass '0' as 'tlb_level' to kvm_pgtable_stage2_flush_range(). [Oliver]
v1:
https://lore.kernel.org/all/[email protected]/
Thank you.
Raghavendra
David Matlack (3):
KVM: Rename kvm_arch_flush_remote_tlb() to
kvm_arch_flush_remote_tlbs()
KVM: Allow range-based TLB invalidation from common code
KVM: Move kvm_arch_flush_remote_tlbs_memslot() to common code
Raghavendra Rao Ananta (11):
KVM: Declare kvm_arch_flush_remote_tlbs() globally
KVM: arm64: Use kvm_arch_flush_remote_tlbs()
KVM: Remove CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
arm64: tlb: Refactor the core flush algorithm of __flush_tlb_range
arm64: tlb: Implement __flush_s2_tlb_range_op()
KVM: arm64: Implement __kvm_tlb_flush_vmid_range()
KVM: arm64: Define kvm_tlb_flush_vmid_range()
KVM: arm64: Implement kvm_arch_flush_remote_tlbs_range()
KVM: arm64: Flush only the memslot after write-protect
KVM: arm64: Invalidate the table entries upon a range
KVM: arm64: Use TLBI range-based instructions for unmap
arch/arm64/include/asm/kvm_asm.h | 3 +
arch/arm64/include/asm/kvm_host.h | 4 +
arch/arm64/include/asm/kvm_pgtable.h | 10 +++
arch/arm64/include/asm/tlbflush.h | 124 +++++++++++++++------------
arch/arm64/kvm/Kconfig | 1 -
arch/arm64/kvm/arm.c | 6 --
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 11 +++
arch/arm64/kvm/hyp/nvhe/tlb.c | 30 +++++++
arch/arm64/kvm/hyp/pgtable.c | 63 ++++++++++++--
arch/arm64/kvm/hyp/vhe/tlb.c | 28 ++++++
arch/arm64/kvm/mmu.c | 16 +++-
arch/mips/include/asm/kvm_host.h | 3 +-
arch/mips/kvm/mips.c | 12 +--
arch/riscv/kvm/mmu.c | 6 --
arch/x86/include/asm/kvm_host.h | 6 +-
arch/x86/kvm/mmu/mmu.c | 26 ++----
arch/x86/kvm/mmu/mmu_internal.h | 3 -
arch/x86/kvm/x86.c | 2 +-
include/linux/kvm_host.h | 24 ++++--
virt/kvm/Kconfig | 3 -
virt/kvm/kvm_main.c | 35 ++++++--
21 files changed, 286 insertions(+), 130 deletions(-)
--
2.41.0.640.ga95def55d0-goog
Currently, during the operations such as a hugepage collapse,
KVM would flush the entire VM's context using 'vmalls12e1is'
TLBI operation. Specifically, if the VM is faulting on many
hugepages (say after dirty-logging), it creates a performance
penalty for the guest whose pages have already been faulted
earlier as they would have to refill their TLBs again.
Instead, leverage kvm_tlb_flush_vmid_range() for table entries.
If the system supports it, only the required range will be
flushed. Else, it'll fallback to the previous mechanism.
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
---
arch/arm64/kvm/hyp/pgtable.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 5d14d5d5819a1..5ef098af17362 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -806,7 +806,8 @@ static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx,
* evicted pte value (if any).
*/
if (kvm_pte_table(ctx->old, ctx->level))
- kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
+ kvm_tlb_flush_vmid_range(mmu, ctx->addr,
+ kvm_granule_size(ctx->level));
else if (kvm_pte_valid(ctx->old))
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu,
ctx->addr, ctx->level);
--
2.41.0.640.ga95def55d0-goog
From: David Matlack <[email protected]>
Move kvm_arch_flush_remote_tlbs_memslot() to common code and drop
"arch_" from the name. kvm_arch_flush_remote_tlbs_memslot() is just a
range-based TLB invalidation where the range is defined by the memslot.
Now that kvm_flush_remote_tlbs_range() can be called from common code we
can just use that and drop a bunch of duplicate code from the arch
directories.
Note this adds a lockdep assertion for slots_lock being held when
calling kvm_flush_remote_tlbs_memslot(), which was previously only
asserted on x86. MIPS has calls to kvm_flush_remote_tlbs_memslot(),
but they all hold the slots_lock, so the lockdep assertion continues to
hold true.
Also drop the CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT ifdef gating
kvm_flush_remote_tlbs_memslot(), since it is no longer necessary.
Signed-off-by: David Matlack <[email protected]>
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
Acked-by: Anup Patel <[email protected]>
---
arch/arm64/kvm/arm.c | 6 ------
arch/mips/kvm/mips.c | 10 ++--------
arch/riscv/kvm/mmu.c | 6 ------
arch/x86/kvm/mmu/mmu.c | 16 +---------------
arch/x86/kvm/x86.c | 2 +-
include/linux/kvm_host.h | 7 +++----
virt/kvm/kvm_main.c | 18 ++++++++++++++++--
7 files changed, 23 insertions(+), 42 deletions(-)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index c2c14059f6a8c..ed7bef4d970b9 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1525,12 +1525,6 @@ void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
}
-void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
- const struct kvm_memory_slot *memslot)
-{
- kvm_flush_remote_tlbs(kvm);
-}
-
static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
struct kvm_arm_device_addr *dev_addr)
{
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 4b7bc39a41736..231ac052b506b 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -199,7 +199,7 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
/* Flush slot from GPA */
kvm_mips_flush_gpa_pt(kvm, slot->base_gfn,
slot->base_gfn + slot->npages - 1);
- kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
+ kvm_flush_remote_tlbs_memslot(kvm, slot);
spin_unlock(&kvm->mmu_lock);
}
@@ -235,7 +235,7 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
needs_flush = kvm_mips_mkclean_gpa_pt(kvm, new->base_gfn,
new->base_gfn + new->npages - 1);
if (needs_flush)
- kvm_arch_flush_remote_tlbs_memslot(kvm, new);
+ kvm_flush_remote_tlbs_memslot(kvm, new);
spin_unlock(&kvm->mmu_lock);
}
}
@@ -987,12 +987,6 @@ int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
return 1;
}
-void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
- const struct kvm_memory_slot *memslot)
-{
- kvm_flush_remote_tlbs(kvm);
-}
-
int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
{
int r;
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index f2eb47925806b..97e129620686c 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -406,12 +406,6 @@ void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
{
}
-void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
- const struct kvm_memory_slot *memslot)
-{
- kvm_flush_remote_tlbs(kvm);
-}
-
void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free)
{
}
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 00f7bda9202f2..43314ca606e2f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6668,7 +6668,7 @@ static void kvm_rmap_zap_collapsible_sptes(struct kvm *kvm,
*/
if (walk_slot_rmaps(kvm, slot, kvm_mmu_zap_collapsible_spte,
PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL - 1, true))
- kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
+ kvm_flush_remote_tlbs_memslot(kvm, slot);
}
void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
@@ -6687,20 +6687,6 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
}
}
-void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
- const struct kvm_memory_slot *memslot)
-{
- /*
- * All current use cases for flushing the TLBs for a specific memslot
- * related to dirty logging, and many do the TLB flush out of mmu_lock.
- * The interaction between the various operations on memslot must be
- * serialized by slots_locks to ensure the TLB flush from one operation
- * is observed by any other operation on the same memslot.
- */
- lockdep_assert_held(&kvm->slots_lock);
- kvm_flush_remote_tlbs_range(kvm, memslot->base_gfn, memslot->npages);
-}
-
void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
const struct kvm_memory_slot *memslot)
{
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a6b9bea62fb8a..faeb2e307b36a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12751,7 +12751,7 @@ static void kvm_mmu_slot_apply_flags(struct kvm *kvm,
* See is_writable_pte() for more details (the case involving
* access-tracked SPTEs is particularly relevant).
*/
- kvm_arch_flush_remote_tlbs_memslot(kvm, new);
+ kvm_flush_remote_tlbs_memslot(kvm, new);
}
}
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 89d2614e4b7a6..394db2ce11e2e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1360,6 +1360,8 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool yield_to_kernel_mode);
void kvm_flush_remote_tlbs(struct kvm *kvm);
void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages);
+void kvm_flush_remote_tlbs_memslot(struct kvm *kvm,
+ const struct kvm_memory_slot *memslot);
#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min);
@@ -1388,10 +1390,7 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
unsigned long mask);
void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot);
-#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
-void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
- const struct kvm_memory_slot *memslot);
-#else /* !CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
+#ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log,
int *is_dirty, struct kvm_memory_slot **memslot);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 26e91000f579d..5d4d2e051aa09 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -379,6 +379,20 @@ void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
kvm_flush_remote_tlbs(kvm);
}
+void kvm_flush_remote_tlbs_memslot(struct kvm *kvm,
+ const struct kvm_memory_slot *memslot)
+{
+ /*
+ * All current use cases for flushing the TLBs for a specific memslot
+ * are related to dirty logging, and many do the TLB flush out of
+ * mmu_lock. The interaction between the various operations on memslot
+ * must be serialized by slots_locks to ensure the TLB flush from one
+ * operation is observed by any other operation on the same memslot.
+ */
+ lockdep_assert_held(&kvm->slots_lock);
+ kvm_flush_remote_tlbs_range(kvm, memslot->base_gfn, memslot->npages);
+}
+
static void kvm_flush_shadow_all(struct kvm *kvm)
{
kvm_arch_flush_shadow_all(kvm);
@@ -2191,7 +2205,7 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
}
if (flush)
- kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
+ kvm_flush_remote_tlbs_memslot(kvm, memslot);
if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
return -EFAULT;
@@ -2308,7 +2322,7 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
KVM_MMU_UNLOCK(kvm);
if (flush)
- kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
+ kvm_flush_remote_tlbs_memslot(kvm, memslot);
return 0;
}
--
2.41.0.640.ga95def55d0-goog
After write-protecting the region, currently KVM invalidates
the entire TLB entries using kvm_flush_remote_tlbs(). Instead,
scope the invalidation only to the targeted memslot. If
supported, the architecture would use the range-based TLBI
instructions to flush the memslot or else fallback to flushing
all of the TLBs.
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
---
arch/arm64/kvm/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 702f8715f9fe7..6f44896936b47 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1083,7 +1083,7 @@ static void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot)
write_lock(&kvm->mmu_lock);
stage2_wp_range(&kvm->arch.mmu, start, end);
write_unlock(&kvm->mmu_lock);
- kvm_flush_remote_tlbs(kvm);
+ kvm_flush_remote_tlbs_memslot(kvm, memslot);
}
/**
--
2.41.0.640.ga95def55d0-goog
Currently, the core TLB flush functionality of __flush_tlb_range()
hardcodes vae1is (and variants) for the flush operation. In the
upcoming patches, the KVM code reuses this core algorithm with
ipas2e1is for range based TLB invalidations based on the IPA.
Hence, extract the core flush functionality of __flush_tlb_range()
into its own macro that accepts an 'op' argument to pass any
TLBI operation, such that other callers (KVM) can benefit.
No functional changes intended.
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
---
arch/arm64/include/asm/tlbflush.h | 121 +++++++++++++++++-------------
1 file changed, 68 insertions(+), 53 deletions(-)
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index 412a3b9a3c25d..b9475a852d5be 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -278,14 +278,74 @@ static inline void flush_tlb_page(struct vm_area_struct *vma,
*/
#define MAX_TLBI_OPS PTRS_PER_PTE
+/*
+ * __flush_tlb_range_op - Perform TLBI operation upon a range
+ *
+ * @op: TLBI instruction that operates on a range (has 'r' prefix)
+ * @start: The start address of the range
+ * @pages: Range as the number of pages from 'start'
+ * @stride: Flush granularity
+ * @asid: The ASID of the task (0 for IPA instructions)
+ * @tlb_level: Translation Table level hint, if known
+ * @tlbi_user: If 'true', call an additional __tlbi_user()
+ * (typically for user ASIDs). 'flase' for IPA instructions
+ *
+ * When the CPU does not support TLB range operations, flush the TLB
+ * entries one by one at the granularity of 'stride'. If the TLB
+ * range ops are supported, then:
+ *
+ * 1. If 'pages' is odd, flush the first page through non-range
+ * operations;
+ *
+ * 2. For remaining pages: the minimum range granularity is decided
+ * by 'scale', so multiple range TLBI operations may be required.
+ * Start from scale = 0, flush the corresponding number of pages
+ * ((num+1)*2^(5*scale+1) starting from 'addr'), then increase it
+ * until no pages left.
+ *
+ * Note that certain ranges can be represented by either num = 31 and
+ * scale or num = 0 and scale + 1. The loop below favours the latter
+ * since num is limited to 30 by the __TLBI_RANGE_NUM() macro.
+ */
+#define __flush_tlb_range_op(op, start, pages, stride, \
+ asid, tlb_level, tlbi_user) \
+do { \
+ int num = 0; \
+ int scale = 0; \
+ unsigned long addr; \
+ \
+ while (pages > 0) { \
+ if (!system_supports_tlb_range() || \
+ pages % 2 == 1) { \
+ addr = __TLBI_VADDR(start, asid); \
+ __tlbi_level(op, addr, tlb_level); \
+ if (tlbi_user) \
+ __tlbi_user_level(op, addr, tlb_level); \
+ start += stride; \
+ pages -= stride >> PAGE_SHIFT; \
+ continue; \
+ } \
+ \
+ num = __TLBI_RANGE_NUM(pages, scale); \
+ if (num >= 0) { \
+ addr = __TLBI_VADDR_RANGE(start, asid, scale, \
+ num, tlb_level); \
+ __tlbi(r##op, addr); \
+ if (tlbi_user) \
+ __tlbi_user(r##op, addr); \
+ start += __TLBI_RANGE_PAGES(num, scale) << PAGE_SHIFT; \
+ pages -= __TLBI_RANGE_PAGES(num, scale); \
+ } \
+ scale++; \
+ } \
+} while (0)
+
static inline void __flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end,
unsigned long stride, bool last_level,
int tlb_level)
{
- int num = 0;
- int scale = 0;
- unsigned long asid, addr, pages;
+ unsigned long asid, pages;
start = round_down(start, stride);
end = round_up(end, stride);
@@ -307,56 +367,11 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
dsb(ishst);
asid = ASID(vma->vm_mm);
- /*
- * When the CPU does not support TLB range operations, flush the TLB
- * entries one by one at the granularity of 'stride'. If the TLB
- * range ops are supported, then:
- *
- * 1. If 'pages' is odd, flush the first page through non-range
- * operations;
- *
- * 2. For remaining pages: the minimum range granularity is decided
- * by 'scale', so multiple range TLBI operations may be required.
- * Start from scale = 0, flush the corresponding number of pages
- * ((num+1)*2^(5*scale+1) starting from 'addr'), then increase it
- * until no pages left.
- *
- * Note that certain ranges can be represented by either num = 31 and
- * scale or num = 0 and scale + 1. The loop below favours the latter
- * since num is limited to 30 by the __TLBI_RANGE_NUM() macro.
- */
- while (pages > 0) {
- if (!system_supports_tlb_range() ||
- pages % 2 == 1) {
- addr = __TLBI_VADDR(start, asid);
- if (last_level) {
- __tlbi_level(vale1is, addr, tlb_level);
- __tlbi_user_level(vale1is, addr, tlb_level);
- } else {
- __tlbi_level(vae1is, addr, tlb_level);
- __tlbi_user_level(vae1is, addr, tlb_level);
- }
- start += stride;
- pages -= stride >> PAGE_SHIFT;
- continue;
- }
-
- num = __TLBI_RANGE_NUM(pages, scale);
- if (num >= 0) {
- addr = __TLBI_VADDR_RANGE(start, asid, scale,
- num, tlb_level);
- if (last_level) {
- __tlbi(rvale1is, addr);
- __tlbi_user(rvale1is, addr);
- } else {
- __tlbi(rvae1is, addr);
- __tlbi_user(rvae1is, addr);
- }
- start += __TLBI_RANGE_PAGES(num, scale) << PAGE_SHIFT;
- pages -= __TLBI_RANGE_PAGES(num, scale);
- }
- scale++;
- }
+ if (last_level)
+ __flush_tlb_range_op(vale1is, start, pages, stride, asid, tlb_level, true);
+ else
+ __flush_tlb_range_op(vae1is, start, pages, stride, asid, tlb_level, true);
+
dsb(ish);
}
--
2.41.0.640.ga95def55d0-goog
kvm_arch_flush_remote_tlbs() or CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
are two mechanisms to solve the same problem, allowing
architecture-specific code to provide a non-IPI implementation of
remote TLB flushing.
Dropping CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL allows KVM to standardize
all architectures on kvm_arch_flush_remote_tlbs() instead of
maintaining two mechanisms.
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
---
virt/kvm/Kconfig | 3 ---
virt/kvm/kvm_main.c | 2 --
2 files changed, 5 deletions(-)
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index b74916de5183a..484d0873061ca 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -62,9 +62,6 @@ config HAVE_KVM_CPU_RELAX_INTERCEPT
config KVM_VFIO
bool
-config HAVE_KVM_ARCH_TLB_FLUSH_ALL
- bool
-
config HAVE_KVM_INVALID_WAKEUPS
bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 70e5479797ac3..d6b0507861550 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -345,7 +345,6 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
}
EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request);
-#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
++kvm->stat.generic.remote_tlb_flush_requests;
@@ -366,7 +365,6 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
++kvm->stat.generic.remote_tlb_flush;
}
EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
-#endif
static void kvm_flush_shadow_all(struct kvm *kvm)
{
--
2.41.0.640.ga95def55d0-goog
From: David Matlack <[email protected]>
Rename kvm_arch_flush_remote_tlb() and the associated macro
__KVM_HAVE_ARCH_FLUSH_REMOTE_TLB to kvm_arch_flush_remote_tlbs() and
__KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS respectively.
Making the name plural matches kvm_flush_remote_tlbs() and makes it more
clear that this function can affect more than one remote TLB.
No functional change intended.
Signed-off-by: David Matlack <[email protected]>
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
---
arch/mips/include/asm/kvm_host.h | 4 ++--
arch/mips/kvm/mips.c | 2 +-
arch/x86/include/asm/kvm_host.h | 4 ++--
include/linux/kvm_host.h | 4 ++--
virt/kvm/kvm_main.c | 2 +-
5 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 04cedf9f88115..9b0ad8f3bf327 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -896,7 +896,7 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
-#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLB
-int kvm_arch_flush_remote_tlb(struct kvm *kvm);
+#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
+int kvm_arch_flush_remote_tlbs(struct kvm *kvm);
#endif /* __MIPS_KVM_HOST_H__ */
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index aa5583a7b05be..4b7bc39a41736 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -981,7 +981,7 @@ void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
}
-int kvm_arch_flush_remote_tlb(struct kvm *kvm)
+int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
{
kvm_mips_callbacks->prepare_flush_shadow(kvm);
return 1;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 28bd38303d704..a2d3cfc2eb75c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1794,8 +1794,8 @@ static inline struct kvm *kvm_arch_alloc_vm(void)
#define __KVM_HAVE_ARCH_VM_FREE
void kvm_arch_free_vm(struct kvm *kvm);
-#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLB
-static inline int kvm_arch_flush_remote_tlb(struct kvm *kvm)
+#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
+static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
{
if (kvm_x86_ops.flush_remote_tlbs &&
!static_call(kvm_x86_flush_remote_tlbs)(kvm))
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 9d3ac7720da9f..e3f968b38ae97 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1479,8 +1479,8 @@ static inline void kvm_arch_free_vm(struct kvm *kvm)
}
#endif
-#ifndef __KVM_HAVE_ARCH_FLUSH_REMOTE_TLB
-static inline int kvm_arch_flush_remote_tlb(struct kvm *kvm)
+#ifndef __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
+static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
{
return -ENOTSUPP;
}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index dfbaafbe3a009..70e5479797ac3 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -361,7 +361,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
* kvm_make_all_cpus_request() reads vcpu->mode. We reuse that
* barrier here.
*/
- if (!kvm_arch_flush_remote_tlb(kvm)
+ if (!kvm_arch_flush_remote_tlbs(kvm)
|| kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
++kvm->stat.generic.remote_tlb_flush;
}
--
2.41.0.640.ga95def55d0-goog
Stop depending on CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL and opt to
standardize on kvm_arch_flush_remote_tlbs() since it avoids
duplicating the generic TLB stats across architectures that implement
their own remote TLB flush.
This adds an extra function call to the ARM64 kvm_flush_remote_tlbs()
path, but that is a small cost in comparison to flushing remote TLBs.
In addition, instead of just incrementing remote_tlb_flush_requests
stat, the generic interface would also increment the
remote_tlb_flush stat.
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
---
arch/arm64/include/asm/kvm_host.h | 2 ++
arch/arm64/kvm/Kconfig | 1 -
arch/arm64/kvm/mmu.c | 6 +++---
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 8b6096753740c..20f2ba149c70c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1111,6 +1111,8 @@ int __init kvm_set_ipa_limit(void);
#define __KVM_HAVE_ARCH_VM_ALLOC
struct kvm *kvm_arch_alloc_vm(void);
+#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
+
static inline bool kvm_vm_is_protected(struct kvm *kvm)
{
return false;
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index f531da6b362e9..6b730fcfee379 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -25,7 +25,6 @@ menuconfig KVM
select MMU_NOTIFIER
select PREEMPT_NOTIFIERS
select HAVE_KVM_CPU_RELAX_INTERCEPT
- select HAVE_KVM_ARCH_TLB_FLUSH_ALL
select KVM_MMIO
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_XFER_TO_GUEST_WORK
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 6db9ef288ec38..0ac721fa27f18 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -161,15 +161,15 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot)
}
/**
- * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8
+ * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8
* @kvm: pointer to kvm structure.
*
* Interface to HYP function to flush all VM TLB entries
*/
-void kvm_flush_remote_tlbs(struct kvm *kvm)
+int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
{
- ++kvm->stat.generic.remote_tlb_flush_requests;
kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
+ return 0;
}
static bool kvm_is_device_pfn(unsigned long pfn)
--
2.41.0.640.ga95def55d0-goog
From: David Matlack <[email protected]>
Make kvm_flush_remote_tlbs_range() visible in common code and create a
default implementation that just invalidates the whole TLB.
This paves the way for several future features/cleanups:
- Introduction of range-based TLBI on ARM.
- Eliminating kvm_arch_flush_remote_tlbs_memslot()
- Moving the KVM/x86 TDP MMU to common code.
No functional change intended.
Signed-off-by: David Matlack <[email protected]>
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
Reviewed-by: Shaoqin Huang <[email protected]>
Reviewed-by: Anup Patel <[email protected]>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/mmu/mmu.c | 10 ++++------
arch/x86/kvm/mmu/mmu_internal.h | 3 ---
include/linux/kvm_host.h | 11 +++++++++++
virt/kvm/kvm_main.c | 13 +++++++++++++
5 files changed, 30 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a2d3cfc2eb75c..b547d17c58f63 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1804,6 +1804,8 @@ static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
return -ENOTSUPP;
}
+#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
+
#define kvm_arch_pmi_in_guest(vcpu) \
((vcpu) && (vcpu)->arch.handling_intr_from_guest)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ec169f5c7dce2..00f7bda9202f2 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -278,16 +278,14 @@ static inline bool kvm_available_flush_remote_tlbs_range(void)
return kvm_x86_ops.flush_remote_tlbs_range;
}
-void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
- gfn_t nr_pages)
+int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
{
int ret = -EOPNOTSUPP;
if (kvm_x86_ops.flush_remote_tlbs_range)
- ret = static_call(kvm_x86_flush_remote_tlbs_range)(kvm, start_gfn,
- nr_pages);
- if (ret)
- kvm_flush_remote_tlbs(kvm);
+ ret = static_call(kvm_x86_flush_remote_tlbs_range)(kvm, gfn, nr_pages);
+
+ return ret;
}
static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index);
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index d39af5639ce97..86cb83bb34804 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -170,9 +170,6 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
struct kvm_memory_slot *slot, u64 gfn,
int min_level);
-void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
- gfn_t nr_pages);
-
/* Flush the given page (huge or not) of guest memory. */
static inline void kvm_flush_remote_tlbs_gfn(struct kvm *kvm, gfn_t gfn, int level)
{
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ade5d4500c2ce..89d2614e4b7a6 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1359,6 +1359,7 @@ int kvm_vcpu_yield_to(struct kvm_vcpu *target);
void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool yield_to_kernel_mode);
void kvm_flush_remote_tlbs(struct kvm *kvm);
+void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages);
#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min);
@@ -1488,6 +1489,16 @@ static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
int kvm_arch_flush_remote_tlbs(struct kvm *kvm);
#endif
+#ifndef __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
+static inline int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
+ gfn_t gfn, u64 nr_pages)
+{
+ return -EOPNOTSUPP;
+}
+#else
+int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages);
+#endif
+
#ifdef __KVM_HAVE_ARCH_NONCOHERENT_DMA
void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d6b0507861550..26e91000f579d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -366,6 +366,19 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
}
EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
+void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
+{
+ if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, nr_pages))
+ return;
+
+ /*
+ * Fall back to a flushing entire TLBs if the architecture range-based
+ * TLB invalidation is unsupported or can't be performed for whatever
+ * reason.
+ */
+ kvm_flush_remote_tlbs(kvm);
+}
+
static void kvm_flush_shadow_all(struct kvm *kvm)
{
kvm_arch_flush_shadow_all(kvm);
--
2.41.0.640.ga95def55d0-goog
On Tue, 15 Aug 2023 23:30:08 +0100,
Sean Christopherson <[email protected]> wrote:
>
> On Fri, Aug 11, 2023, Raghavendra Rao Ananta wrote:
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index ec169f5c7dce2..00f7bda9202f2 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -278,16 +278,14 @@ static inline bool kvm_available_flush_remote_tlbs_range(void)
> > return kvm_x86_ops.flush_remote_tlbs_range;
> > }
> >
> > -void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
> > - gfn_t nr_pages)
> > +int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
> > {
> > int ret = -EOPNOTSUPP;
> >
> > if (kvm_x86_ops.flush_remote_tlbs_range)
> > - ret = static_call(kvm_x86_flush_remote_tlbs_range)(kvm, start_gfn,
> > - nr_pages);
> > - if (ret)
> > - kvm_flush_remote_tlbs(kvm);
> > + ret = static_call(kvm_x86_flush_remote_tlbs_range)(kvm, gfn, nr_pages);
> > +
> > + return ret;
>
> Please write this as
>
> if (kvm_x86_ops.flush_remote_tlbs_range)
> return static_call(kvm_x86_flush_remote_tlbs_range)(kvm, gfn, nr_pages);
>
> return -EOPNOTSUPP;
>
> or alternatively
>
> if (!kvm_x86_ops.flush_remote_tlbs_range)
> return -EOPNOTSUPP;
>
> return static_call(kvm_x86_flush_remote_tlbs_range)(kvm, gfn, nr_pages);
>
> Hmm, I'll throw my official vote for the second version.
I've applied the second version locally.
M.
--
Without deviation from the norm, progress is not possible.
On Fri, 11 Aug 2023 04:51:13 +0000, Raghavendra Rao Ananta wrote:
> In certain code paths, KVM/ARM currently invalidates the entire VM's
> page-tables instead of just invalidating a necessary range. For example,
> when collapsing a table PTE to a block PTE, instead of iterating over
> each PTE and flushing them, KVM uses 'vmalls12e1is' TLBI operation to
> flush all the entries. This is inefficient since the guest would have
> to refill the TLBs again, even for the addresses that aren't covered
> by the table entry. The performance impact would scale poorly if many
> addresses in the VM is going through this remapping.
>
> [...]
Applied to next, thanks!
[01/14] KVM: Rename kvm_arch_flush_remote_tlb() to kvm_arch_flush_remote_tlbs()
commit: a1342c8027288e345cc5fd16c6800f9d4eb788ed
[02/14] KVM: Declare kvm_arch_flush_remote_tlbs() globally
commit: cfb0c08e80120928dda1e951718be135abd49bae
[03/14] KVM: arm64: Use kvm_arch_flush_remote_tlbs()
commit: 32121c813818a87ba7565b3afce93a9cc3610a22
[04/14] KVM: Remove CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
commit: eddd21481011008792f4e647a5244f6e15970abc
[05/14] KVM: Allow range-based TLB invalidation from common code
commit: d4788996051e3c07fadc6d9b214073fcf78810a8
[06/14] KVM: Move kvm_arch_flush_remote_tlbs_memslot() to common code
commit: 619b5072443c05cf18c31b2c0320cdb42396d411
[07/14] arm64: tlb: Refactor the core flush algorithm of __flush_tlb_range
commit: 360839027a6e4c022e8cbaa373dd747185f1e0a5
[08/14] arm64: tlb: Implement __flush_s2_tlb_range_op()
commit: 4d73a9c13aaa78b149ac04b02f0ee7973f233bfa
[09/14] KVM: arm64: Implement __kvm_tlb_flush_vmid_range()
commit: 6354d15052ec88273c24beae4c99e31c3d3889b6
[10/14] KVM: arm64: Define kvm_tlb_flush_vmid_range()
commit: 117940aa6e5f8308f1529e1313660980f1dae771
[11/14] KVM: arm64: Implement kvm_arch_flush_remote_tlbs_range()
commit: c42b6f0b1cde4dd19e6b5dd052e67b87cc331b01
[12/14] KVM: arm64: Flush only the memslot after write-protect
commit: 3756b6f2bb3a242fef0867b39a23607f5aeca138
[13/14] KVM: arm64: Invalidate the table entries upon a range
commit: defc8cc7abf0fcee8d73e440ee02827348d060e0
[14/14] KVM: arm64: Use TLBI range-based instructions for unmap
commit: 7657ea920c54218f123ddc1b572821695b669c13
Cheers,
M.
--
Without deviation from the norm, progress is not possible.