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=1794063419; b=xQXIktQsU2cNcviCtPWZdxnfD0aDByl9HbtQZbP2HWBj91vPcj6kW49rO5lDF2RqD8ZJ +01hVHZjPr6ftr1HCOYxk9KSKElQWyJZKailj/5Dd5+STw6lPVhi9yRsNJBy0+uq6eX0q 9PSifZE8w63REaArIDtftzN5olEmvBXzoDAJZKDBq6grqYtQMsrHLIlkjSTEW2MLQ/Kgt Mw1JBQGBMWjgclmEZUvJQwHPV6UOa3cl/QETl830CAcith+tpEShjiHL4PtIjiXwMXbXm AFvJJ/EPfyGw1kw9uaFNKmPsrWY/kEClH/mwnqLtbCOfG7i4XuV1NLO0KuyNbvTQchg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063419; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=xOfDpDM8Z558ZiMFbEGNx3dYnRiopJCq4695R5xL7is=; b=dYZYDwAMiQADzcUWgDULZC801qBGA5lb60g81gjoBGGqFXPleb0VvU/V2qBxyeNdCeqc 90ESiuI1RCyUwigryK+9AU5IkN4gQm5yilbg/IuVHyol5l4kOVeEv+VQmybHHCu8bqhYP WfZnC9tPEgdLLPyzycqEIE5HwbeTagOsyWr6SlhvV+xm8A0i5pY4VYjyzJ22fXYrzqnOW x0BVzb24TWwHdOEWMHjx6dK/Atga+nZ5cLY4ntKiZIheEKSeGsKZP7SRx8S6NBuvfaqSu N82hIIfXwmTRYoFGFSKzYdyohqiORjAzlsSaBoYx3VrSyHvo88B8OVWBJFNnPXa4rdQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=aeaSY6kr; 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 2623F606D80B; Sat, 7 Nov 2026 14:56:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=aeaSY6kr Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7D8C1F0089F; Sat, 7 Nov 2026 14:56:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063419; bh=xOfDpDM8Z558ZiMFbEGNx3dYnRiopJCq4695R5xL7is=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=aeaSY6krljczNTYPGdeGfZnAEYvaM/tCddOyzVeNlgp0KvA2CVBWlY9kw+oLj/01/ C7Y10bPcjo4+aSikREI6zJFqcJRkJEBS/mlmd7HXa7djq65TLcXeuep2OfK99GKHVs Z5fMgMKDm54TLa6RY1IQ12vLntgRMgq/j3ME5uX0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fuad Tabba , Marc Zyngier , Sasha Levin Subject: [PATCH 6.18 586/869] KVM: arm64: Move IN_GUEST_MODE ahead of state being loaded Date: Sat, 7 Nov 2026 08:54:28 -0500 Message-ID: <20261107134913.016299183@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Sasha Levin --- arch/arm64/kvm/arm.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index ab01b6c961132..c8a8d9ce4b14e 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1229,31 +1229,33 @@ 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 */ - if (kvm_vcpu_has_pmu(vcpu)) - 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_arch_vcpu_ctxflush_fp(vcpu); /************************************************************** -- 2.53.0