From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8817ACA0FF9 for ; Sat, 30 Aug 2025 00:50:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=hub4YsLY+/WRUv/60d464Jwc8ZXJrJFaMLX2QqmBFVo=; b=y09/HOlDSRXukQ uy13qFM0TETBQTJ8tL9+a4h9FauIzBxIgzeRMtlKi4eO4dw5SwSscz0dLqXOXWJ+Gzv+RLpEeb1zw m6uGqvM6EXqJ6XC20yUKRIqgbNfsE4Svt+PdtmpCsGZE7tx3tPrlrtpcjjOGyXBkrf6ZCjUsbS9uK xesE5Aar/xssOo+sG/Hf84fD7l2tACehgLuCJAiR1XX0UVoCFXOvUPHE+mhpz+WIva3o56eWl9b/g DeZWGVqnEKiMNVyAlvfqhKkz0aqghRHa7iq7bo298rwkXMgRYFBgzzSi5oy6HHCxAtxUZkhIvBlhM 1ggsWtOPBy13UAHoWFdg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1us9nz-00000007Blb-0mpk; Sat, 30 Aug 2025 00:50:55 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1us3zP-00000006ekr-1i0N; Fri, 29 Aug 2025 18:38:19 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 78B0660147; Fri, 29 Aug 2025 18:38:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 838E8C4CEF0; Fri, 29 Aug 2025 18:38:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756492698; bh=G2OtD6gg+bw9ZqOkq99RiwmobzpQGmczBt388tEvqQA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ov5WnNhDYY/E6a4awYJM+K8xgExCClE5Y0Tf2Y11//SUqC2e8H33VSZ3i1uc1POtL 3YeCHPT+LRLLcXNmGQk3C5oHa7zsZ0bofiQBgc3pMXL6VH0tJuaARC3EPbSqo4icNK 2wfmzXZxZK8E2DR8zjmoS3hnPuPIA3PoPtUqF3bYgIyCzxtY0eWIORQko0EVjTH3+9 ZfDkkyLHld0blZUJ+7o4K80ZpSREI4kfSUqIc7jMHAmBsnDS9BGcDpLvn6Kaz95vU6 U4WSMzFdzrnSt8Z0481GORe3zvOMdHZ8W4AuagPsc8gBnpvZu0IxNoyLS2Jq773s7J 3OXrT9D8lO56A== Date: Fri, 29 Aug 2025 18:38:16 +0000 From: Wei Liu To: Sean Christopherson Cc: Marc Zyngier , Oliver Upton , Catalin Marinas , Will Deacon , Tianrui Zhao , Bibo Mao , Huacai Chen , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Peter Zijlstra , Andy Lutomirski , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, loongarch@lists.linux.dev, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-hyperv@vger.kernel.org, rcu@vger.kernel.org, Nuno Das Neves , Mukesh R , ssengar@linux.microsoft.com, namjain@linux.microsoft.com Subject: Re: [PATCH v2 2/7] Drivers: hv: Disentangle VTL return cancellation from SIGPENDING Message-ID: References: <20250828000156.23389-1-seanjc@google.com> <20250828000156.23389-3-seanjc@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20250828000156.23389-3-seanjc@google.com> X-BeenThere: kvm-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kvm-riscv" Errors-To: kvm-riscv-bounces+kvm-riscv=archiver.kernel.org@lists.infradead.org On Wed, Aug 27, 2025 at 05:01:51PM -0700, Sean Christopherson wrote: > Check for return to a lower VTL being cancelled separately from handling > pending TIF-based work, as there is no need to immediately process pending > work; the kernel will immediately exit to userspace (ignoring preemption) > and handle the pending work at that time. > > Disentangling cancellation from the TIF-based work will allow switching to > common virtualization APIs for detecting and processing pending work. > > Signed-off-by: Sean Christopherson Thanks for this patch, Sean. My current plan is to drop this driver from my tree (hence it will disappear from linux-next soon) because Peter has an objection to the ABI it introduces. I just have not gotten around to it yet. I won't apply this patch, the next one and the last one. I have CC'ed the owner of that driver to this patch here so that your suggestion can be incorporated in future submissions. CC Saurabh and Naman. Thanks, Wei > --- > drivers/hv/mshv_vtl_main.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/hv/mshv_vtl_main.c b/drivers/hv/mshv_vtl_main.c > index 12f5e77b7095..aa09a76f0eff 100644 > --- a/drivers/hv/mshv_vtl_main.c > +++ b/drivers/hv/mshv_vtl_main.c > @@ -731,19 +731,21 @@ static int mshv_vtl_ioctl_return_to_lower_vtl(void) > _TIF_NOTIFY_RESUME | _TIF_NOTIFY_SIGNAL | > _TIF_NEED_RESCHED_LAZY; > unsigned long ti_work; > - u32 cancel; > unsigned long irq_flags; > struct hv_vp_assist_page *hvp; > int ret; > > local_irq_save(irq_flags); > + if (READ_ONCE(mshv_vtl_this_run()->cancel)) { > + local_irq_restore(irq_flags); > + preempt_enable(); > + return -EINTR; > + } > + > ti_work = READ_ONCE(current_thread_info()->flags); > - cancel = READ_ONCE(mshv_vtl_this_run()->cancel); > - if (unlikely((ti_work & VTL0_WORK) || cancel)) { > + if (unlikely(ti_work & VTL0_WORK)) { > local_irq_restore(irq_flags); > preempt_enable(); > - if (cancel) > - ti_work |= _TIF_SIGPENDING; > ret = mshv_do_pre_guest_mode_work(ti_work); > if (ret) > return ret; > -- > 2.51.0.268.g9569e192d0-goog > > -- kvm-riscv mailing list kvm-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kvm-riscv