From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F3A470 for ; Thu, 17 Jun 2021 15:02:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=V9go7Y/UucnNrXIa1S8r+WI1e5UGRrj5UmJdJeNO/dA=; b=DH3TBb6PTIQLbsLVSV75pzrQdw YOvlaQGhwgDxkO+n6YHcCAQcekOch3TTkgmTSQyJSG+PTfbr9rhv8w+vKtjZcSboPUa0yed3OM6Xv O2jUrIlTuYUi1y9vgYNACiS7Lc+7ouOb55q+Nq6PJsitEvRbdvdo2XiQhbmMvNFacge2ptH3eu7lm kSPZJfLJpFpr7d6jZ/bbyyUf75MzrK66LY/+Mz9z5jfs6Fexynhfz7Qqc0uisvf4WVdV/gybL68W9 5mQy5IpZrCBaK6A9Zus6JuMao0B8Fy0DFPW3ThfNH2q2ELD5/gn0XQHA7VNHkqqrlpUPYOsjOVAqp ixUOZqwg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1lttVj-009Fr5-UE; Thu, 17 Jun 2021 15:00:57 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 48ADC300252; Thu, 17 Jun 2021 17:00:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 31A2A2BD52F2F; Thu, 17 Jun 2021 17:00:48 +0200 (CEST) Date: Thu, 17 Jun 2021 17:00:48 +0200 From: Peter Zijlstra To: Joerg Roedel Cc: x86@kernel.org, Joerg Roedel , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , Arvind Sankar , linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v6 1/2] x86/sev: Make sure IRQs are disabled while GHCB is active Message-ID: References: <20210616184913.13064-1-joro@8bytes.org> <20210616184913.13064-2-joro@8bytes.org> X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210616184913.13064-2-joro@8bytes.org> On Wed, Jun 16, 2021 at 08:49:12PM +0200, Joerg Roedel wrote: > static void sev_es_ap_hlt_loop(void) > { > struct ghcb_state state; > + unsigned long flags; > struct ghcb *ghcb; > > - ghcb = sev_es_get_ghcb(&state); > + local_irq_save(flags); > + > + ghcb = __sev_get_ghcb(&state); > > while (true) { > vc_ghcb_invalidate(ghcb); > @@ -692,7 +704,9 @@ static void sev_es_ap_hlt_loop(void) > break; > } > > - sev_es_put_ghcb(&state); > + __sev_put_ghcb(&state); > + > + local_irq_restore(flags); > } I think this is broken, at this point RCU is quite dead on this CPU and local_irq_save/restore include tracing and all sorts. Also, shouldn't IRQs already be disabled by the time we get here? 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Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1lttVj-009Fr5-UE; Thu, 17 Jun 2021 15:00:57 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 48ADC300252; Thu, 17 Jun 2021 17:00:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 31A2A2BD52F2F; Thu, 17 Jun 2021 17:00:48 +0200 (CEST) Date: Thu, 17 Jun 2021 17:00:48 +0200 From: Peter Zijlstra To: Joerg Roedel Subject: Re: [PATCH v6 1/2] x86/sev: Make sure IRQs are disabled while GHCB is active Message-ID: References: <20210616184913.13064-1-joro@8bytes.org> <20210616184913.13064-2-joro@8bytes.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210616184913.13064-2-joro@8bytes.org> Cc: kvm@vger.kernel.org, Dave Hansen , virtualization@lists.linux-foundation.org, Arvind Sankar , hpa@zytor.com, Jiri Slaby , x86@kernel.org, David Rientjes , Martin Radev , Tom Lendacky , Joerg Roedel , Kees Cook , Cfir Cohen , linux-coco@lists.linux.dev, Andy Lutomirski , Dan Williams , Juergen Gross , Mike Stunes , Sean Christopherson , linux-kernel@vger.kernel.org, Masami Hiramatsu , Erdem Aktas X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Wed, Jun 16, 2021 at 08:49:12PM +0200, Joerg Roedel wrote: > static void sev_es_ap_hlt_loop(void) > { > struct ghcb_state state; > + unsigned long flags; > struct ghcb *ghcb; > > - ghcb = sev_es_get_ghcb(&state); > + local_irq_save(flags); > + > + ghcb = __sev_get_ghcb(&state); > > while (true) { > vc_ghcb_invalidate(ghcb); > @@ -692,7 +704,9 @@ static void sev_es_ap_hlt_loop(void) > break; > } > > - sev_es_put_ghcb(&state); > + __sev_put_ghcb(&state); > + > + local_irq_restore(flags); > } I think this is broken, at this point RCU is quite dead on this CPU and local_irq_save/restore include tracing and all sorts. Also, shouldn't IRQs already be disabled by the time we get here? _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization