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Message-ID: <20240809194335.1726916-12-seanjc@google.com>
Date: Fri, 9 Aug 2024 12:43:23 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
Oliver Upton <oliver.upton@...ux.dev>, Marc Zyngier <maz@...nel.org>, Peter Xu <peterx@...hat.com>,
James Houghton <jthoughton@...gle.com>
Subject: [PATCH 11/22] KVM: x86/mmu: Plumb a @can_yield parameter into __walk_slot_rmaps()
Add a @can_yield param to __walk_slot_rmaps() to control whether or not
dropping mmu_lock and conditionally rescheduling is allowed. This will
allow using __walk_slot_rmaps() and thus cond_resched() to handle
mmu_notifier invalidations, which usually allow blocking/yielding, but not
when invoked by the OOM killer.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/kvm/mmu/mmu.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 676cb7dfcbf9..a5a7e476f5bb 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1545,7 +1545,8 @@ static __always_inline bool __walk_slot_rmaps(struct kvm *kvm,
slot_rmaps_handler fn,
int start_level, int end_level,
gfn_t start_gfn, gfn_t end_gfn,
- bool flush_on_yield, bool flush)
+ bool can_yield, bool flush_on_yield,
+ bool flush)
{
struct slot_rmap_walk_iterator iterator;
@@ -1556,6 +1557,9 @@ static __always_inline bool __walk_slot_rmaps(struct kvm *kvm,
if (iterator.rmap)
flush |= fn(kvm, iterator.rmap, slot);
+ if (!can_yield)
+ continue;
+
if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
if (flush && flush_on_yield) {
kvm_flush_remote_tlbs_range(kvm, start_gfn,
@@ -1577,7 +1581,7 @@ static __always_inline bool walk_slot_rmaps(struct kvm *kvm,
{
return __walk_slot_rmaps(kvm, slot, fn, start_level, end_level,
slot->base_gfn, slot->base_gfn + slot->npages - 1,
- flush_on_yield, false);
+ true, flush_on_yield, false);
}
static __always_inline bool walk_slot_rmaps_4k(struct kvm *kvm,
@@ -6528,7 +6532,7 @@ static bool kvm_rmap_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_e
flush = __walk_slot_rmaps(kvm, memslot, __kvm_zap_rmap,
PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
- start, end - 1, true, flush);
+ start, end - 1, true, true, flush);
}
}
@@ -6816,7 +6820,7 @@ static void kvm_shadow_mmu_try_split_huge_pages(struct kvm *kvm,
*/
for (level = KVM_MAX_HUGEPAGE_LEVEL; level > target_level; level--)
__walk_slot_rmaps(kvm, slot, shadow_mmu_try_split_huge_pages,
- level, level, start, end - 1, true, false);
+ level, level, start, end - 1, true, true, false);
}
/* Must be called with the mmu_lock held in write-mode. */
--
2.46.0.76.ge559c4bf1a-goog
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