From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794329238; b=fsDzbG7jUg3KSA3jgi11l7Z4wixHg+qxyqF0xztJfSXhHtqeTX5jqm/CMULXgf6KWaHC I1M2RW6AVNS0zwAfzn8hhj2J/ftw0D06+tpOKuxjiercctWP1irvHUEH51iulwsdcslLe 8/gkMMUM7Et42gvakeH5jpIy8l10gfuqgox+EVq+nmKZ+KQX4rzNfcu1Fg6WwIyqAS6Yk lTL2QEYOyafjEa6dwe3Zd184zHC5Bbuom8flYtH2Beu/oKGEFqhzcgjfUxsmHGW5J8D2j 0jFq5z9VGZl1+IXacLYyoRIRiN7yVIeQpKHOJKjZsMlLIQD1MiUdJz8S6H/+ks7Ti6Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794329238; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=gt/SsjE9JCoEMycWMqmG33EQL+W1whATBG7Wqtbg5+8=; b=qFqgXxjiphoph7YE+iA3jD1Fl40e6cmzaT9CDVJZe9MQfzaSOxDmcMHHuPeuB1vbzzFJ FI6XnSmAHYp2SuM9oPHkObE9JZ5uGLv+Xkp5ypZah6/atM+SCvJSfDFrjlJIqr8Y11jrX snqH8jx1rqg5WXJ0tywJB7UhJZyw8rEvtHpa12DRX6kyMcG3ZrJJ8HQrf0HXDeYsgxnHf ePSe/QdvLYUKD4i6aizv8uKV9E/EJZ4xFQyKGurKAr8TefluqdnwvCM3m4bHc5aWvZGGT +T8XQlIg+4X5W0InVmKBfpcVwMceLqMSMipwGA3eKhtd+T5vWSTbogwX6HTCp7yMd2g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=oi4berdK; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51A5A606A323 for ; Tue, 10 Nov 2026 16:47:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=oi4berdK Received: by smtp.kernel.org (Postfix) with ESMTPSA id 559811F008A2; Tue, 10 Nov 2026 16:47:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794329237; bh=gt/SsjE9JCoEMycWMqmG33EQL+W1whATBG7Wqtbg5+8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oi4berdKU8nkO1jvqpnTJ3670vd5Mp5JZt8/5ldF7KNfoaPV4xEW329zWl7IMZmXx 5/HSZX0m1+XHZVBQT/l3BxKW5SY1guXjnS9SCHi9xBqduPhdEfa04C+3Y8jdbdBiXV /qxpdsySAYuyuNsdcTD8nTjZs9v0ZRjb5/IslOk01fwT8KdOdRj2kzE69LLh1e4AIN Kqm0OehfQNtT6ndSN/7bWe2FtJ561AY4xASE+0W2XVv4vxkAd75tEm97MPns6lHTNC ffSR/BvTar6mlk0wJmEL2mrY8oC3am7WmA1GV29+3bizsP83zI2a7Kfunn9Uqk4egx YaKUJGPjfK4Jg== From: Sasha Levin To: stable@vger.kernel.org Cc: Marc Zyngier , Fuad Tabba , Sasha Levin Subject: [PATCH 6.1.y] KVM: arm64: Move IN_GUEST_MODE ahead of state being loaded Date: Tue, 10 Nov 2026 11:47:15 -0500 Message-ID: <20261110164645.2583842-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107054938-failed-6.1-22b6557ad05b@kernel.org> References: <20261107054938-failed-6.1-22b6557ad05b@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Marc Zyngier [ Upstream commit 22b6557ad05bf05c73246f62c19af3e04017270e ] IN_GUEST_MODE is advertised too late, when state has already been moved onto CPU registers and cannot be observed by another CPU anymore. Move the IN_GUEST_MODE publication ahead of the state being loaded, and immediately check for pending request. This ensures that there is no window of opportunity for another CPU to observe OUTSIDE_GUEST_MODE and yet for state to be loaded. This also simplifies the "state rollback", which solely amounts to synchronising the timer when no irqchip is present. Cc: stable@vger.kernel.org Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Link: https://patch.msgid.link/20261015100539.1011760-4-maz@kernel.org Signed-off-by: Marc Zyngier [ sashal: adapted kvm_pmu_sync_hwstate() removal to code without the kvm_vcpu_has_pmu() guard ] Signed-off-by: Sasha Levin --- arch/arm64/kvm/arm.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index b0b1324e84097..be99f1a88bd4c 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -923,30 +923,33 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) local_irq_disable(); - kvm_vgic_flush_hwstate(vcpu); - - kvm_pmu_update_vcpu_events(vcpu); - /* * Ensure we set mode to IN_GUEST_MODE after we disable * interrupts and before the final VCPU requests check. * See the comment in kvm_vcpu_exiting_guest_mode() and * Documentation/virt/kvm/vcpu-requests.rst + * + * Requests to self must be posted before this point, or + * won't be taken into account until the next exit. No state + * loading other than what happens at vcpu_load() time can + * be done before we have checked for pending requests. */ smp_store_mb(vcpu->mode, IN_GUEST_MODE); if (ret <= 0 || kvm_vcpu_exit_request(vcpu, &ret)) { - isb(); /* Ensure work in x_flush_hwstate is committed */ - kvm_pmu_sync_hwstate(vcpu); if (unlikely(!irqchip_in_kernel(vcpu->kvm))) kvm_timer_sync_user(vcpu); - kvm_vgic_sync_hwstate(vcpu); smp_store_release(&vcpu->mode, OUTSIDE_GUEST_MODE); local_irq_enable(); preempt_enable(); continue; } + /* From here onwards, we are commited to entering the guest */ + kvm_vgic_flush_hwstate(vcpu); + + kvm_pmu_update_vcpu_events(vcpu); + kvm_arm_setup_debug(vcpu); kvm_arch_vcpu_ctxflush_fp(vcpu); -- 2.53.0