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Message-Id: <20200218210736.16432-3-sean.j.christopherson@intel.com>
Date: Tue, 18 Feb 2020 13:07:16 -0800
From: Sean Christopherson <sean.j.christopherson@...el.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Paul Mackerras <paulus@...abs.org>,
Christian Borntraeger <borntraeger@...ibm.com>,
Janosch Frank <frankja@...ux.ibm.com>,
David Hildenbrand <david@...hat.com>,
Cornelia Huck <cohuck@...hat.com>,
Sean Christopherson <sean.j.christopherson@...el.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>, Marc Zyngier <maz@...nel.org>,
James Morse <james.morse@....com>,
Julien Thierry <julien.thierry.kdev@...il.com>,
Suzuki K Poulose <suzuki.poulose@....com>,
linux-mips@...r.kernel.org, kvm@...r.kernel.org,
kvm-ppc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.cs.columbia.edu, linux-kernel@...r.kernel.org,
Christoffer Dall <christoffer.dall@....com>,
Peter Xu <peterx@...hat.com>,
Philippe Mathieu-Daudé <f4bug@...at.org>
Subject: [PATCH v6 02/22] KVM: Reinstall old memslots if arch preparation fails
Reinstall the old memslots if preparing the new memory region fails
after invalidating a to-be-{re}moved memslot.
Remove the superfluous 'old_memslots' variable so that it's somewhat
clear that the error handling path needs to free the unused memslots,
not simply the 'old' memslots.
Fixes: bc6678a33d9b9 ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update")
Reviewed-by: Christoffer Dall <christoffer.dall@....com>
Reviewed-by: Peter Xu <peterx@...hat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
virt/kvm/kvm_main.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 67ae2d5c37b2..ac9c7c103453 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -999,7 +999,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
unsigned long npages;
struct kvm_memory_slot *slot;
struct kvm_memory_slot old, new;
- struct kvm_memslots *slots = NULL, *old_memslots;
+ struct kvm_memslots *slots;
int as_id, id;
enum kvm_mr_change change;
@@ -1107,7 +1107,13 @@ int __kvm_set_memory_region(struct kvm *kvm,
slot = id_to_memslot(slots, id);
slot->flags |= KVM_MEMSLOT_INVALID;
- old_memslots = install_new_memslots(kvm, as_id, slots);
+ /*
+ * We can re-use the old memslots, the only difference from the
+ * newly installed memslots is the invalid flag, which will get
+ * dropped by update_memslots anyway. We'll also revert to the
+ * old memslots if preparing the new memory region fails.
+ */
+ slots = install_new_memslots(kvm, as_id, slots);
/* From this point no new shadow pages pointing to a deleted,
* or moved, memslot will be created.
@@ -1117,13 +1123,6 @@ int __kvm_set_memory_region(struct kvm *kvm,
* - kvm_is_visible_gfn (mmu_check_root)
*/
kvm_arch_flush_shadow_memslot(kvm, slot);
-
- /*
- * We can re-use the old_memslots from above, the only difference
- * from the currently installed memslots is the invalid flag. This
- * will get overwritten by update_memslots anyway.
- */
- slots = old_memslots;
}
r = kvm_arch_prepare_memory_region(kvm, &new, mem, change);
@@ -1137,15 +1136,17 @@ int __kvm_set_memory_region(struct kvm *kvm,
}
update_memslots(slots, &new, change);
- old_memslots = install_new_memslots(kvm, as_id, slots);
+ slots = install_new_memslots(kvm, as_id, slots);
kvm_arch_commit_memory_region(kvm, mem, &old, &new, change);
kvm_free_memslot(kvm, &old, &new);
- kvfree(old_memslots);
+ kvfree(slots);
return 0;
out_slots:
+ if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
+ slots = install_new_memslots(kvm, as_id, slots);
kvfree(slots);
out_free:
kvm_free_memslot(kvm, &new, &old);
--
2.24.1
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