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Message-ID: <20231105163040.14904-12-pbonzini@redhat.com>
Date: Sun, 5 Nov 2023 17:30:14 +0100
From: Paolo Bonzini <pbonzini@...hat.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>,
Oliver Upton <oliver.upton@...ux.dev>,
Huacai Chen <chenhuacai@...nel.org>,
Michael Ellerman <mpe@...erman.id.au>,
Anup Patel <anup@...infault.org>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Sean Christopherson <seanjc@...gle.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.linux.dev, linux-mips@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org,
linux-riscv@...ts.infradead.org, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Xiaoyao Li <xiaoyao.li@...el.com>,
Xu Yilun <yilun.xu@...el.com>,
Chao Peng <chao.p.peng@...ux.intel.com>,
Fuad Tabba <tabba@...gle.com>,
Jarkko Sakkinen <jarkko@...nel.org>,
Anish Moorthy <amoorthy@...gle.com>,
David Matlack <dmatlack@...gle.com>,
Yu Zhang <yu.c.zhang@...ux.intel.com>,
Isaku Yamahata <isaku.yamahata@...el.com>,
Mickaël Salaün <mic@...ikod.net>,
Vlastimil Babka <vbabka@...e.cz>,
Vishal Annapurve <vannapurve@...gle.com>,
Ackerley Tng <ackerleytng@...gle.com>,
Maciej Szmigiero <mail@...iej.szmigiero.name>,
David Hildenbrand <david@...hat.com>,
Quentin Perret <qperret@...gle.com>,
Michael Roth <michael.roth@....com>,
Wang <wei.w.wang@...el.com>,
Liam Merwick <liam.merwick@...cle.com>,
Isaku Yamahata <isaku.yamahata@...il.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH 11/34] KVM: Drop .on_unlock() mmu_notifier hook
From: Sean Christopherson <seanjc@...gle.com>
Drop the .on_unlock() mmu_notifer hook now that it's no longer used for
notifying arch code that memory has been reclaimed. Adding .on_unlock()
and invoking it *after* dropping mmu_lock was a terrible idea, as doing so
resulted in .on_lock() and .on_unlock() having divergent and asymmetric
behavior, and set future developers up for failure, i.e. all but asked for
bugs where KVM relied on using .on_unlock() to try to run a callback while
holding mmu_lock.
Opportunistically add a lockdep assertion in kvm_mmu_invalidate_end() to
guard against future bugs of this nature.
Reported-by: Isaku Yamahata <isaku.yamahata@...el.com>
Link: https://lore.kernel.org/all/20230802203119.GB2021422@ls.amr.corp.intel.com
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>
Reviewed-by: Fuad Tabba <tabba@...gle.com>
Tested-by: Fuad Tabba <tabba@...gle.com>
Message-Id: <20231027182217.3615211-12-seanjc@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
virt/kvm/kvm_main.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e18a7f152c0b..7f3291dec7a6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -544,7 +544,6 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
typedef void (*on_lock_fn_t)(struct kvm *kvm);
-typedef void (*on_unlock_fn_t)(struct kvm *kvm);
struct kvm_mmu_notifier_range {
/*
@@ -556,7 +555,6 @@ struct kvm_mmu_notifier_range {
union kvm_mmu_notifier_arg arg;
gfn_handler_t handler;
on_lock_fn_t on_lock;
- on_unlock_fn_t on_unlock;
bool flush_on_ret;
bool may_block;
};
@@ -663,11 +661,8 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
if (range->flush_on_ret && r.ret)
kvm_flush_remote_tlbs(kvm);
- if (r.found_memslot) {
+ if (r.found_memslot)
KVM_MMU_UNLOCK(kvm);
- if (!IS_KVM_NULL_FN(range->on_unlock))
- range->on_unlock(kvm);
- }
srcu_read_unlock(&kvm->srcu, idx);
@@ -687,7 +682,6 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
.arg = arg,
.handler = handler,
.on_lock = (void *)kvm_null_fn,
- .on_unlock = (void *)kvm_null_fn,
.flush_on_ret = true,
.may_block = false,
};
@@ -706,7 +700,6 @@ static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn
.end = end,
.handler = handler,
.on_lock = (void *)kvm_null_fn,
- .on_unlock = (void *)kvm_null_fn,
.flush_on_ret = false,
.may_block = false,
};
@@ -813,7 +806,6 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
.end = range->end,
.handler = kvm_mmu_unmap_gfn_range,
.on_lock = kvm_mmu_invalidate_begin,
- .on_unlock = (void *)kvm_null_fn,
.flush_on_ret = true,
.may_block = mmu_notifier_range_blockable(range),
};
@@ -891,7 +883,6 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
.end = range->end,
.handler = (void *)kvm_null_fn,
.on_lock = kvm_mmu_invalidate_end,
- .on_unlock = (void *)kvm_null_fn,
.flush_on_ret = false,
.may_block = mmu_notifier_range_blockable(range),
};
--
2.39.1
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