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KVM: x86/mmu: Assert that correct locks are held for page write-tracking

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When adding/removing gfns to/from write-tracking, assert that mmu_lock
is held for write, and that either slots_lock or kvm->srcu is held.
mmu_lock must be held for write to protect gfn_write_track's refcount,
and SRCU or slots_lock must be held to protect the memslot itself.

Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-26-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2023-07-28 18:35:31 -07:00 committed by Paolo Bonzini
parent 7b574863e7
commit e18c5429e0
1 changed files with 11 additions and 6 deletions
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17
arch/x86/kvm/mmu/page_track.c
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@ -12,6 +12,7 @@
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/lockdep.h>
#include <linux/kvm_host.h>
#include <linux/rculist.h>
@ -77,9 +78,6 @@ static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn,
* add guest page to the tracking pool so that corresponding access on that
* page will be intercepted.
*
* It should be called under the protection both of mmu-lock and kvm->srcu
* or kvm->slots_lock.
*
* @kvm: the guest instance we are interested in.
* @slot: the @gfn belongs to.
* @gfn: the guest page.
@ -87,6 +85,11 @@ static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn,
void kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot,
gfn_t gfn)
{
lockdep_assert_held_write(&kvm->mmu_lock);
lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
srcu_read_lock_held(&kvm->srcu));
if (WARN_ON_ONCE(!kvm_page_track_write_tracking_enabled(kvm)))
return;
@ -107,9 +110,6 @@ EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn);
* remove the guest page from the tracking pool which stops the interception
* of corresponding access on that page.
*
* It should be called under the protection both of mmu-lock and kvm->srcu
* or kvm->slots_lock.
*
* @kvm: the guest instance we are interested in.
* @slot: the @gfn belongs to.
* @gfn: the guest page.
@ -117,6 +117,11 @@ EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn);
void kvm_write_track_remove_gfn(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn)
{
lockdep_assert_held_write(&kvm->mmu_lock);
lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
srcu_read_lock_held(&kvm->srcu));
if (WARN_ON_ONCE(!kvm_page_track_write_tracking_enabled(kvm)))
return;