From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B7E74A07 for ; Tue, 9 Sep 2025 00:00:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757376049; cv=none; b=rq0zBpV1VVyMW6rOmusejdvJhOTNVzdMGFVipc2QdG/dq1nJQ1y6KydmCT/PkyXd76wgJ+84AbNyJIhmAAQfNFSCp0PgtpR09iWjL0VtNxpPJ4VxqiSdMdMBuiMFfNSO0NPOeJ2CcIaKtipjf01YmpWJeisBt972z6FblMriJeQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757376049; c=relaxed/simple; bh=t43UlVpJasRoQxmkSV3wU/+OU03S3iZK+XwFqLne8/4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=S/lKzfhPoykJZE4bJTSRfP3BAl+NXGJkLK/+ktK3954237aKQGO4WzS74NQnsA/u9hQtxUFslYL2EBM5gJmejnwort7AuI+udaNYFnj9PztCFN62I3c16ClxPNiprgCzCXN9Gac8ihRQF9yt/wa0kOIFkefQ9RP7/sHM5p3qi8A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=lTibQFap; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="lTibQFap" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-32811874948so4308135a91.2 for ; Mon, 08 Sep 2025 17:00:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1757376047; x=1757980847; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=HsJSTvORJeiE9AQsY+DJV4sYMEZ3S3aUT20uePDrvh0=; b=lTibQFapm4QWn/J4TXdRViO1Oa/uzU51tR71zZJD/Cmos7nHNkHrvckXhmmFavL+KU QcY0Ce8ZnVW/UNFGQuUUI9nW2SCeIe/Bad0wW5eEDyv4DncaPOgakPmDl2Tla2gi9S/F OpyzEB/2qNbR4W74Bn7NwQOFRCpQiShgZWj+obyV57zBpcFpYijFO8u4bT5J2FcEfBcA toDy24WT+lB7pevWOakh6MjQI5Geo5E9YiOqoYiTkguySRsoj6qEqByvjj1F9GSekB1a tqRGUhHxIgEXnvRyi345ln2pds1Mq2yCcM5cOUlrcdbMn38mS5PHJhKPTommFZfI/MdV riTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757376047; x=1757980847; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=HsJSTvORJeiE9AQsY+DJV4sYMEZ3S3aUT20uePDrvh0=; b=kto/8Ts2NPBRpP65KD5pbsOfj6UdR34GKtBdf8vbrpkikXRzkpAwV6zi1Vjmsr4m2t OV8jjLJ8IzoE8iKb5YMm/T4xJw48oUVbzo+4vozDF3yTUXXgzrpE7+/wCsKRkjF5RU9J Z4bCgHkgEbckBI2BfY2AfoMVg7uoLiT7f3UlRnRaXWUGgNgbar0p/WFI5uaYCHNLraHT D/txk7PwbtTeTi+kcW6Oo7of+0PcW1SekZgA7LmEHVZ+ebGWfpYr/ORLJxzjqDMn2tUA CM+gV1elSepgSgTNo0qzjUkxcve2zWmrCqb9QGiw+z9iuTDrsDmauTszJNKqZkRwZTgG 7yFQ== X-Gm-Message-State: AOJu0YzF/8O9HkrePnHCQIjPRcD7dlletrFCYQKVfO6m+p736YpyGqP0 5HMF8PKNDSC6PK0dJbUO78gcjRw87iepcLL6eYUl1tpNEnyFz9GcnfV89vLBF8zH9YAl2fFC+7z TNGwugQ== X-Google-Smtp-Source: AGHT+IGN+rw9t4njipIiYxG3sgW7qTh9wknWMp/Sn0+Kp9pr6wiAlds7UuRQrwUPPIjws8ivFi1cX3gkDSc= X-Received: from pjbsv16.prod.google.com ([2002:a17:90b:5390:b0:327:7035:d848]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:3c83:b0:32b:be68:bb35 with SMTP id 98e67ed59e1d1-32d440cf991mr11855628a91.36.1757376047061; Mon, 08 Sep 2025 17:00:47 -0700 (PDT) Date: Mon, 8 Sep 2025 17:00:45 -0700 In-Reply-To: <20250908212925.708769718@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250908212737.353775467@linutronix.de> <20250908212925.708769718@linutronix.de> Message-ID: Subject: Re: [patch V4 07/36] rseq, virt: Retrigger RSEQ after vcpu_run() From: Sean Christopherson To: Thomas Gleixner Cc: LKML , Michael Jeanson , Jens Axboe , Paolo Bonzini , Wei Liu , Dexuan Cui , Mathieu Desnoyers , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , x86@kernel.org, Arnd Bergmann , Heiko Carstens , Christian Borntraeger , Sven Schnelle , Huacai Chen , Paul Walmsley , Palmer Dabbelt Content-Type: text/plain; charset="us-ascii" On Mon, Sep 08, 2025, Thomas Gleixner wrote: > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -49,6 +49,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -4466,6 +4467,8 @@ static long kvm_vcpu_ioctl(struct file * > r = kvm_arch_vcpu_ioctl_run(vcpu); > vcpu->wants_to_run = false; > Finally had a lightbulb moment as to how to eat this hack while not stonewalling the entire series. Can you add something like: /* * FIXME: Remove this hack once all KVM architectures support * the generic TIF bits, i.e. a dedicated TIF_RSEQ. */ to discourage further abuse, and to make it clear that such ugliness isn't anyone's first choice. With that, Acked-by: Sean Christopherson > + rseq_virt_userspace_exit(); > + > trace_kvm_userspace_exit(vcpu->run->exit_reason, r); > break; > } >