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=1794047736; b=HlMKKhGzAqVHWGMtPNJbPBiCFTSjwQKGboHFOAze3qcEiFXOkWEb+3w7V33XzyWK07fK vihHkIdc9Zo71d/CRVd5xZDxxdWnmimiU2DP0BZQHFCufXwubfQhgqojARZpkjy/ou2Vf 699PmgIW5JkE/D+cmHUup+Mh/B7nPUU6NmB6nXa4U4I2ZfsyNkPlIsMWqy1YiyUxzDnQu 80UfsZPFT9/KfsR/ckjCOLhr5LwGVfyGefkXIfMRstOOkoo8jp0AKb1ywzFJZmpxfPwyn uE5y/F6SYWJX72lVz9/adC3nu9hUF8lj+73s3lJppz/Hij2dwWvf6J4tgfaw5K44CjQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794047736; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=iao7xs7HFuiXIPcRFEo+g5tBLwQg1VYoJ6hpzJjiihA=; b=vns2w8o+CCuJEU7KxL198MlxcT38avl+52Lqm8t3As3xZJ2l9V+xtMaYWNJrvCKjo61R Q6blXVRggj+ZRqO9ZiQiBbw/8GxdAf7qCJmPUWkuwqPh74A9TN4jmNBytumAYSYRP+S05 SaV8ASXBkPM4whdoGztBTIZ3MKkySBJWdlxKXeM665sUiGdhViowBv7EEw19ShvAEQCaV AeB+CiYU7u190zPvjQnCU/5hEb4XZCMMQiCE8vYUvEoMci2GZsInn97Al1vT6Xxa6AfMJ IzLVzGkgs8Bgr9UgU/DnRHZfdtdgJeLp9yaq7PfQEmiVTcqoibIMwC4R9d2klXxodJA== 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=LrjXfXp1; 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 18CD6606A32D for ; Sat, 7 Nov 2026 10:35:36 +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=LrjXfXp1 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DBC31F0089F; Sat, 7 Nov 2026 10:35:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794047736; bh=iao7xs7HFuiXIPcRFEo+g5tBLwQg1VYoJ6hpzJjiihA=; h=From:To:Cc:Subject:Date; b=LrjXfXp1YO7wWq1Zb1IgWAxxKTAfpTKfpPkNWR9kZwsooUwhppT3vdeU2/DsuWrtI 9m3Q+uJrqo3NIlSnD/4FA8jly5pEIpVX4Mr3bsz5YFA2tArRZo7ozDYJJXWYkrlc6y LnTup1exmK5nWzdBWZDlNYpgNcuuuBhIboXaEtimB6rCQaqfmpJEntC9nQGND0Z4M5 tFHCrF1Y3OsC6uqavFxLlNsvpJWIxOaA+6xf5wYCAiFPtwnmEc0k65upybBaS+WOEn B5m15+17tg8PVARvqQTQpU8HfOYtblZ1xg3nps3RVX1zT4tMX4z48+U9W0IEWvs9E+ bTwFpt0pXZRxQ== From: Sasha Levin To: maz@kernel.org, fuad.tabba@linux.dev Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] KVM: arm64: Move IN_GUEST_MODE ahead of state being loaded" failed to apply to 6.6-stable tree Date: Sat, 7 Nov 2026 05:35:34 -0500 Message-ID: <20261107053534-failed-6.6-22b6557ad05b@kernel.org> X-Mailer: git-send-email 2.53.0 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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 22b6557ad05bf05c73246f62c19af3e04017270e # git commit -s git send-email --to '' --in-reply-to '20261107053534-failed-6.6-22b6557ad05b@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 22b6557ad05bf05c73246f62c19af3e04017270e Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 15 Oct 2026 11:05:35 +0100 Subject: [PATCH] KVM: arm64: Move IN_GUEST_MODE ahead of state being loaded 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 --- 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 7ce9f3bfa7fff..cadc82ba5a5a0 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1321,31 +1321,33 @@ 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