KVM ARM Archive on lore.kernel.org
 help / color / Atom feed
From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "James Hogan" <jhogan@kernel.org>,
	"Paul Mackerras" <paulus@ozlabs.org>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Janosch Frank" <frankja@linux.ibm.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Marc Zyngier" <marc.zyngier@arm.com>
Cc: Wanpeng Li <wanpengli@tencent.com>,
	kvm@vger.kernel.org, David Hildenbrand <david@redhat.com>,
	linux-arm-kernel@lists.infradead.org,
	Joerg Roedel <joro@8bytes.org>, Cornelia Huck <cohuck@redhat.com>,
	linux-mips@vger.kernel.org,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	kvmarm@lists.cs.columbia.edu, Jim Mattson <jmattson@google.com>
Subject: [PATCH 01/13] KVM: Reinstall old memslots if arch preparation fails
Date: Wed, 11 Sep 2019 11:50:26 -0700
Message-ID: <20190911185038.24341-2-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190911185038.24341-1-sean.j.christopherson@intel.com>

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")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.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 c6a91b044d8d..daa5de5b3f88 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -923,7 +923,7 @@ 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;
 
@@ -1031,7 +1031,13 @@ 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.
@@ -1041,13 +1047,6 @@ int __kvm_set_memory_region(struct kvm *kvm,
 		 *	- kvm_is_visible_gfn (mmu_check_roots)
 		 */
 		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);
@@ -1061,15 +1060,17 @@ 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);
-- 
2.22.0

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-11 18:50 [PATCH 00/13] KVM: Dynamically size memslot arrays Sean Christopherson
2019-09-11 18:50 ` Sean Christopherson [this message]
2019-09-11 18:50 ` [PATCH 02/13] KVM: PPC: Move memslot memory allocation into prepare_memory_region() Sean Christopherson
2019-09-19  0:23   ` Paul Mackerras
2019-09-11 18:50 ` [PATCH 03/13] KVM: x86: Allocate memslot resources during prepare_memory_region() Sean Christopherson
2019-09-11 18:50 ` [PATCH 04/13] KVM: Drop kvm_arch_create_memslot() Sean Christopherson
2019-09-12 11:31   ` Janosch Frank
2019-09-11 18:50 ` [PATCH 05/13] KVM: Refactor error handling for setting memory region Sean Christopherson
2019-09-12 11:36   ` Janosch Frank
2019-09-11 18:50 ` [PATCH 06/13] KVM: Move setting of memslot into helper routine Sean Christopherson
2019-09-11 18:50 ` [PATCH 07/13] KVM: Move memslot deletion to helper function Sean Christopherson
2019-09-11 18:50 ` [PATCH 08/13] KVM: Simplify kvm_free_memslot() and all its descendents Sean Christopherson
2019-09-11 18:50 ` [PATCH 09/13] KVM: Clean up local variable usage in __kvm_set_memory_region() Sean Christopherson
2019-09-11 18:50 ` [PATCH 10/13] KVM: Provide common implementation for generic dirty log functions Sean Christopherson
2019-09-19  0:22   ` Paul Mackerras
2019-09-19 19:39     ` Sean Christopherson
2019-09-11 18:50 ` [PATCH 11/13] KVM: Ensure validity of memslot with respect to kvm_get_dirty_log() Sean Christopherson
2019-09-11 18:50 ` [PATCH 12/13] KVM: Terminate memslot walks via used_slots Sean Christopherson
2019-09-11 18:50 ` [PATCH 13/13] KVM: Dynamically size memslot array based on number of used slots Sean Christopherson

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190911185038.24341-2-sean.j.christopherson@intel.com \
    --to=sean.j.christopherson@intel.com \
    --cc=borntraeger@de.ibm.com \
    --cc=cohuck@redhat.com \
    --cc=david@redhat.com \
    --cc=frankja@linux.ibm.com \
    --cc=jhogan@kernel.org \
    --cc=jmattson@google.com \
    --cc=joro@8bytes.org \
    --cc=kvm-ppc@vger.kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mips@vger.kernel.org \
    --cc=marc.zyngier@arm.com \
    --cc=paulus@ozlabs.org \
    --cc=pbonzini@redhat.com \
    --cc=rkrcmar@redhat.com \
    --cc=vkuznets@redhat.com \
    --cc=wanpengli@tencent.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

KVM ARM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/kvmarm/0 kvmarm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 kvmarm kvmarm/ https://lore.kernel.org/kvmarm \
		kvmarm@lists.cs.columbia.edu
	public-inbox-index kvmarm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/edu.columbia.cs.lists.kvmarm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git