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 lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (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 4B391C4450A for ; Thu, 16 Jul 2026 11:07:12 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wkJvY-0006ns-EP; Thu, 16 Jul 2026 07:06:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wkJvW-0006ma-59 for qemu-devel@nongnu.org; Thu, 16 Jul 2026 07:06:50 -0400 Received: from linux.microsoft.com ([13.77.154.182]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wkJvT-0003HE-EI for qemu-devel@nongnu.org; Thu, 16 Jul 2026 07:06:48 -0400 Received: from linux.microsoft.com (unknown [167.220.197.183]) by linux.microsoft.com (Postfix) with ESMTPSA id 3522120B7167; Thu, 16 Jul 2026 04:06:32 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 3522120B7167 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1784199994; bh=r9bcdXskcSuKd2g0BrAyoEPN5qq+H7GaU2HModfNBtE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ELn0lebGwYjdgvGN9yd2MuJmDgX10K3JNe62/piK2vzT54YulwGkGkh79J3JRrZO8 Pl8UJi4T5KyngPD78QwVUh5eTCI0nCPlw7E35YqQq1BgZRdp2IqiRQI8IpHP6yNXGv 1Ps5P0ijIx8rIfFOWQgsMAGVtnF5tljIp523WDDM= Date: Thu, 16 Jul 2026 14:06:32 +0300 From: Doru =?iso-8859-1?Q?Bl=E2nzeanu?= To: Magnus Kulke Cc: qemu-devel@nongnu.org, Paolo Bonzini , Zhao Liu , Richard Henderson , Magnus Kulke , "Michael S. Tsirkin" , Wei Liu , Doru =?iso-8859-1?Q?Bl=E2nzeanu?= , Wei Liu Subject: Re: [PATCH 01/12] target/i386/mshv: disable AMX TILE features Message-ID: References: <20260710101534.664604-1-magnuskulke@linux.microsoft.com> <20260710101534.664604-2-magnuskulke@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260710101534.664604-2-magnuskulke@linux.microsoft.com> Received-SPF: pass client-ip=13.77.154.182; envelope-from=dblanzeanu@linux.microsoft.com; helo=linux.microsoft.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Jul 10, 2026 at 12:15:23PM +0200, Magnus Kulke wrote: > For the time being we disable AMX TILE in partition processor features > and CPUID b/c AMX TILE XSAVE state (XTILE_DATA) is 8KB, which exceeds > the current fixed 4KB XSAVE buffer size. > > For now we filter it until buffer sizing is computed dynamically from CPUID. > > Signed-off-by: Magnus Kulke > --- > accel/mshv/mshv-all.c | 8 ++++++++ > target/i386/mshv/mshv-cpu.c | 16 ++++++++++++++++ > 2 files changed, 24 insertions(+) > > diff --git a/accel/mshv/mshv-all.c b/accel/mshv/mshv-all.c > index 72721d0f0d..5e8756ede2 100644 > --- a/accel/mshv/mshv-all.c > +++ b/accel/mshv/mshv-all.c > @@ -203,6 +203,14 @@ static int create_partition(int mshv_fd, int *vm_fd) > > /* enable all */ > disabled_xsave_features.as_uint64 = 0; > + /* > + * AMX TILE XSAVE state (XTILE_DATA) is 8KB, which exceeds the > + * current fixed 4KB XSAVE buffer size. > + */ > + disabled_xsave_features.amx_tile_support = 1; > + disabled_xsave_features.amx_bf16_support = 1; > + disabled_xsave_features.amx_int8_support = 1; > + disabled_xsave_features.amx_fp16_support = 1; > > /* > * query host for supported processor features and disable unsupported > diff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c > index 1c433c408c..8eca01a8fa 100644 > --- a/target/i386/mshv/mshv-cpu.c > +++ b/target/i386/mshv/mshv-cpu.c > @@ -2156,6 +2156,22 @@ uint32_t mshv_get_supported_cpuid(uint32_t func, uint32_t idx, int reg) > */ > ret &= ~CPUID_7_0_ECX_LA57; > } > + if (func == 0x07 && idx == 0 && reg == R_EDX) { > + /* > + * AMX TILE XSAVE state (XTILE_DATA) is 8KB, which exceeds the > + * current fixed 4KB XSAVE buffer size. Filter until buffer > + * sizing is computed dynamically from CPUID. > + */ > + ret &= ~CPUID_7_0_EDX_AMX_TILE; > + ret &= ~CPUID_7_0_EDX_AMX_BF16; > + ret &= ~CPUID_7_0_EDX_AMX_INT8; > + } > + if (func == 0x07 && idx == 1 && reg == R_EAX) { > + ret &= ~CPUID_7_1_EAX_AMX_FP16; > + } > + if (func == 0x07 && idx == 1 && reg == R_EDX) { > + ret &= ~CPUID_7_1_EDX_AMX_COMPLEX; > + } > > return ret; > } > -- > 2.34.1 Reviewed-by: Doru Blânzeanu