From: Marc Zyngier <maz@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>, Gavin Shan <gshan@redhat.com>,
kvm@vger.kernel.org, kernel-team@android.com,
Steven Price <steven.price@arm.com>,
Eric Auger <eric.auger@redhat.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/9] KVM: arm64: pvtime: Fix potential loss of stolen time
Date: Fri, 4 Sep 2020 11:45:23 +0100 [thread overview]
Message-ID: <20200904104530.1082676-3-maz@kernel.org> (raw)
In-Reply-To: <20200904104530.1082676-1-maz@kernel.org>
From: Andrew Jones <drjones@redhat.com>
We should only check current->sched_info.run_delay once when
updating stolen time. Otherwise there's a chance there could
be a change between checks that we miss (preemption disabling
comes after vcpu request checks).
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200804170604.42662-3-drjones@redhat.com
---
arch/arm64/kvm/pvtime.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c
index c3ef4ebd6846..95f9580275b1 100644
--- a/arch/arm64/kvm/pvtime.c
+++ b/arch/arm64/kvm/pvtime.c
@@ -13,6 +13,7 @@
void kvm_update_stolen_time(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
+ u64 last_steal = vcpu->arch.steal.last_steal;
u64 steal;
__le64 steal_le;
u64 offset;
@@ -24,8 +25,8 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu)
/* Let's do the local bookkeeping */
steal = vcpu->arch.steal.steal;
- steal += current->sched_info.run_delay - vcpu->arch.steal.last_steal;
- vcpu->arch.steal.last_steal = current->sched_info.run_delay;
+ vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay);
+ steal += vcpu->arch.steal.last_steal - last_steal;
vcpu->arch.steal.steal = steal;
steal_le = cpu_to_le64(steal);
--
2.27.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-09-04 10:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 10:45 [GIT PULL] KVM/arm64 fixes for 5.9 Marc Zyngier
2020-09-04 10:45 ` [PATCH 1/9] KVM: arm64: pvtime: steal-time is only supported when configured Marc Zyngier
2020-09-04 10:45 ` Marc Zyngier [this message]
2020-09-04 10:45 ` [PATCH 3/9] KVM: arm64: Drop type input from kvm_put_guest Marc Zyngier
2020-09-04 10:45 ` [PATCH 4/9] KVM: arm64: pvtime: Fix stolen time accounting across migration Marc Zyngier
2020-09-04 10:45 ` [PATCH 5/9] KVM: Documentation: Minor fixups Marc Zyngier
2020-09-04 10:45 ` [PATCH 6/9] arm64/x86: KVM: Introduce steal-time cap Marc Zyngier
2020-09-04 10:45 ` [PATCH 7/9] KVM: arm64: Do not try to map PUDs when they are folded into PMD Marc Zyngier
2020-09-09 3:23 ` Punit Agrawal
2020-09-04 10:45 ` [PATCH 8/9] KVM: arm64: Fix address truncation in traces Marc Zyngier
2020-09-04 10:45 ` [PATCH 9/9] KVM: arm64: Update page shift if stage 2 block mapping not supported Marc Zyngier
2020-09-09 15:20 ` [GIT PULL] KVM/arm64 fixes for 5.9 Paolo Bonzini
2020-09-09 17:15 ` Marc Zyngier
2020-09-09 17:20 ` Paolo Bonzini
Reply instructions:
You may reply publicly 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=20200904104530.1082676-3-maz@kernel.org \
--to=maz@kernel.org \
--cc=alexandru.elisei@arm.com \
--cc=drjones@redhat.com \
--cc=eric.auger@redhat.com \
--cc=gshan@redhat.com \
--cc=kernel-team@android.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=pbonzini@redhat.com \
--cc=steven.price@arm.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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).