From: Peter Zijlstra <peterz@infradead.org>
To: Joerg Roedel <joro@8bytes.org>
Cc: x86@kernel.org, Joerg Roedel <jroedel@suse.de>,
hpa@zytor.com, Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Jiri Slaby <jslaby@suse.cz>,
Dan Williams <dan.j.williams@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Juergen Gross <jgross@suse.com>,
Kees Cook <keescook@chromium.org>,
David Rientjes <rientjes@google.com>,
Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
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
Date: Thu, 17 Jun 2021 17:00:48 +0200 [thread overview]
Message-ID: <YMtjoLLQpKyveVlS@hirez.programming.kicks-ass.net> (raw)
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?
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Joerg Roedel <joro@8bytes.org>
Cc: kvm@vger.kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
virtualization@lists.linux-foundation.org,
Arvind Sankar <nivedita@alum.mit.edu>,
hpa@zytor.com, Jiri Slaby <jslaby@suse.cz>,
x86@kernel.org, David Rientjes <rientjes@google.com>,
Martin Radev <martin.b.radev@gmail.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Joerg Roedel <jroedel@suse.de>, Kees Cook <keescook@chromium.org>,
Cfir Cohen <cfir@google.com>,
linux-coco@lists.linux.dev, Andy Lutomirski <luto@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Juergen Gross <jgross@suse.com>, Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <seanjc@google.com>,
linux-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Erdem Aktas <erdemaktas@google.com>
Subject: Re: [PATCH v6 1/2] x86/sev: Make sure IRQs are disabled while GHCB is active
Date: Thu, 17 Jun 2021 17:00:48 +0200 [thread overview]
Message-ID: <YMtjoLLQpKyveVlS@hirez.programming.kicks-ass.net> (raw)
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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next prev parent reply other threads:[~2021-06-17 15:02 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-16 18:49 [PATCH v6 0/2] x86/sev: Fixes for SEV-ES Guest Support Joerg Roedel
2021-06-16 18:49 ` Joerg Roedel
2021-06-16 18:49 ` [PATCH v6 1/2] x86/sev: Make sure IRQs are disabled while GHCB is active Joerg Roedel
2021-06-16 18:49 ` Joerg Roedel
2021-06-17 15:00 ` Peter Zijlstra [this message]
2021-06-17 15:00 ` Peter Zijlstra
2021-06-18 8:25 ` Joerg Roedel
2021-06-18 8:25 ` Joerg Roedel
2021-06-17 15:38 ` Peter Zijlstra
2021-06-17 15:38 ` Peter Zijlstra
2021-06-18 8:17 ` Joerg Roedel
2021-06-18 8:17 ` Joerg Roedel
2021-06-18 10:53 ` Peter Zijlstra
2021-06-18 10:53 ` Peter Zijlstra
2021-06-16 18:49 ` [PATCH v6 2/2] x86/sev: Split up runtime #VC handler for correct state tracking Joerg Roedel
2021-06-16 18:49 ` Joerg Roedel
2021-06-17 13:55 ` [PATCH v6.1 " Joerg Roedel
2021-06-17 13:55 ` Joerg Roedel
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