Received-SPF: pass (google.com: domain of linux-kernel+bounces-146287-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Date: Mon, 15 Apr 2024 22:47:47 -0700
From: Dan Williams <dan.j.williams@intel.com>
To: Tom Lendacky <thomas.lendacky@amd.com>, <linux-kernel@vger.kernel.org>,
	<x86@kernel.org>, <linux-coco@lists.linux.dev>, <svsm-devel@coconut-svsm.dev>
CC: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>, "Peter
 Zijlstra" <peterz@infradead.org>, Dan Williams <dan.j.williams@intel.com>,
	Michael Roth <michael.roth@amd.com>, Ashish Kalra <ashish.kalra@amd.com>,
	Joel Becker <jlbec@evilplan.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v3 13/14] x86/sev: Hide SVSM attestation entries if not
 running under an SVSM
Message-ID: <661e110326bd2_4d5612949a@dwillia2-mobl3.amr.corp.intel.com.notmuch>
References: <cover.1711405593.git.thomas.lendacky@amd.com>
 <67893f352bc54de61160bfe251cba0bdf0431f37.1711405593.git.thomas.lendacky@amd.com>
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <67893f352bc54de61160bfe251cba0bdf0431f37.1711405593.git.thomas.lendacky@amd.com>
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?/2OmrA8wKpgTHK7QfRVVMjbw3/1sPSBEKWyPx8ok0vZ+BdJML3BZum6QSgnp?=
 =?us-ascii?Q?v2zEoSzUwKQPAUy/hv6dQwtv1U/PTf0E6BuMoOCiE3raltSkFumR/gK0THzB?=
 =?us-ascii?Q?FWVvuPiEaIxQRW0E8qcRdEu/JGDLfeR/J3PmnAszc/3Yhm3VyrnFFq6QSbii?=
 =?us-ascii?Q?c6O8BbCnI1TEyCIitmeWOc3RQ5r+i8sOzoZzeZl8S7oldPhYulJOBAeOXK5V?=
 =?us-ascii?Q?CLMMrnCzMpVJ02NC8FG0HmBRTFtxnaFiS1PRKxO2nXw2TqcPe2cQ/hafta30?=
 =?us-ascii?Q?O4uOy98qT6waDNz9+yat+2DsCno9YnK5F2mylr4NyH+6oEgpNSLBLkUlyzKy?=
 =?us-ascii?Q?4nDATIiftKF/dZortQYEir7NMHJd7hnzKrEdRypX52td2vCiTnX9EaVzS2l4?=
 =?us-ascii?Q?fREdjKGQXt7/sgElLYNu69+DK81mW9DiavfGQM/2lpA8chRwvNQD8PZyS137?=
 =?us-ascii?Q?ejpMHrfyYXwHJ3tNIotLoivgbnRVdp5pqeIqJZbGhckEThq8f8mmkPE+wxt5?=
 =?us-ascii?Q?S4UQlQivX2x+HTKDyDNmG5/XL4cq/lJ1epgBJyI72SNO8GdIG6jcQKaIueC/?=
 =?us-ascii?Q?P86nNFIfTHiWqpqiGGOncGkx17hcXuWFuzzz4UdBE2SQGu60I9QpC/ZjBHG7?=
 =?us-ascii?Q?iRPHhIa3HbtZw33hXFp4pPlkDaPZhCUaaV8Ut9Ik2cw17pYFXrKPvog2MPvz?=
 =?us-ascii?Q?rztzG0HGRmJTQVpymSmDvytOdKGJOsZv0tiVG3FeXNf4OAiihvJUJISoLBHy?=
 =?us-ascii?Q?ZQD0f02uljr12IsG4xfdy+hhxZcoyeU6P9DTrAFQvzgqotV9fgjYxXQFL9GF?=
 =?us-ascii?Q?CX4LbxGHD8TesIQuhbaB1tsvKmButjPmKSHsyrbzIq/lhNNnvfAuv6487adg?=
 =?us-ascii?Q?rFswIUsy3rApOupjFUsHz6gPlEyIkbcKHj0CbXL02ExysTX4eoYJcr/RTACk?=
 =?us-ascii?Q?FJB9H7t/jpxN41ddu2I2P+Wkp9g9HIqbQgrmcDWpFeJIAxj8P/9t+UjhCLpA?=
 =?us-ascii?Q?68CE1ezZU2tuWhLbDrYB1qDM/2qUY81+CDHU142Ss6EoWUg0cmh3qQyNs0iD?=
 =?us-ascii?Q?gADDj3dw3+syQZS97FXPfyjObuuGIA4qSQWIZpQefugQ2iZ3aKE+JTEuTr9X?=
 =?us-ascii?Q?ntUEVdG74wzKNo3OAgkJy4uE0jIlNVeWmPM16rMGjVPTGRdrRSd8PY9WdPl4?=
 =?us-ascii?Q?VSZ39fyBAjRA6LEmnrlqSKuqUfLtS8o2qz8B4xdtur6lrlslbJstSJTi2viJ?=
 =?us-ascii?Q?0wF1ZPIA1yZDWAUcJRle4mXHEPHDuMG4853awCMo7PsdAr2H95Jki5n5Tu9V?=
 =?us-ascii?Q?kCOGLAxTXZ7xY/d2poUW/k75YGScKkwVOFsryLEkeKOSYEcFnjtwqY/fArOh?=
 =?us-ascii?Q?rfJkr8kVby5ahTUaeroDPPHaNKpOHhDNrRX6DxY04YUeGbzTHYjw5EYZweXC?=
 =?us-ascii?Q?Uc/ssIPz69BCXskuiCPl098WcOKS7XhKvfVZnAlFFKKp3o9UPnxJYwpjDpGJ?=
 =?us-ascii?Q?Yy3MsAb4ZjNIM8VqvQV3Hpvu9X8S//q+FVc1/rZIrxzauh2MSAbVegUE66za?=
 =?us-ascii?Q?ZCE4pdu344tm0H6HbtseLWpIXvNnbJPmaXhobsRtA+JW69QNFMJpVhZexakv?=
 =?us-ascii?Q?Kg=3D=3D?=
X-MS-Exchange-CrossTenant-Network-Message-Id: d67f88df-645f-4483-0159-08dc5dd8c202
X-MS-Exchange-CrossTenant-AuthSource: PH8PR11MB8107.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Apr 2024 05:47:52.9812
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: Zai/OhcCnysKvadDQjz+O5fbN8cCqr1pKRjYhQObgFXHMpOIj8L5jetwvtuYnh0CK56c3U9JsOskcnHxUGazDkjuqHf+YVwL324MroGSpjA=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN9PR11MB5322
X-OriginatorOrg: intel.com

Tom Lendacky wrote:
> Config-fs provides support to hide individual attribute entries. Using
> this support, base the display of the SVSM related entries on the presence
> of an SVSM.
> 
> Cc: Joel Becker <jlbec@evilplan.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/coco/core.c        |  4 ++++
>  drivers/virt/coco/tsm.c     | 14 ++++++++++----
>  include/linux/cc_platform.h |  8 ++++++++
>  3 files changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
> index d07be9d05cd0..efa0f648f754 100644
> --- a/arch/x86/coco/core.c
> +++ b/arch/x86/coco/core.c
> @@ -12,6 +12,7 @@
>  
>  #include <asm/coco.h>
>  #include <asm/processor.h>
> +#include <asm/sev.h>
>  
>  enum cc_vendor cc_vendor __ro_after_init = CC_VENDOR_NONE;
>  u64 cc_mask __ro_after_init;
> @@ -78,6 +79,9 @@ static bool noinstr amd_cc_platform_has(enum cc_attr attr)
>  	case CC_ATTR_GUEST_STATE_ENCRYPT:
>  		return sev_status & MSR_AMD64_SEV_ES_ENABLED;
>  
> +	case CC_ATTR_GUEST_SVSM_PRESENT:
> +		return snp_get_vmpl();
> +
>  	/*
>  	 * With SEV, the rep string I/O instructions need to be unrolled
>  	 * but SEV-ES supports them through the #VC handler.
> diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm.c
> index 46f230bf13ac..d30471874e87 100644
> --- a/drivers/virt/coco/tsm.c
> +++ b/drivers/virt/coco/tsm.c
> @@ -64,6 +64,12 @@ static struct tsm_report_state *to_state(struct tsm_report *report)
>  	return container_of(report, struct tsm_report_state, report);
>  }
>  
> +static bool provider_visibility(const struct config_item *item,
> +				const struct configfs_attribute *attr)
> +{
> +	return cc_platform_has(CC_ATTR_GUEST_SVSM_PRESENT);
> +}
> +
>  static int try_advance_write_generation(struct tsm_report *report)
>  {
>  	struct tsm_report_state *state = to_state(report);
> @@ -144,7 +150,7 @@ static ssize_t tsm_report_service_provider_store(struct config_item *cfg,
>  
>  	return len;
>  }
> -CONFIGFS_ATTR_WO(tsm_report_, service_provider);
> +CONFIGFS_ATTR_VISIBLE_WO(tsm_report_, service_provider, provider_visibility);
>  
>  static ssize_t tsm_report_service_guid_store(struct config_item *cfg,
>  					     const char *buf, size_t len)
> @@ -165,7 +171,7 @@ static ssize_t tsm_report_service_guid_store(struct config_item *cfg,
>  
>  	return len;
>  }
> -CONFIGFS_ATTR_WO(tsm_report_, service_guid);
> +CONFIGFS_ATTR_VISIBLE_WO(tsm_report_, service_guid, provider_visibility);
>  
>  static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg,
>  							 const char *buf, size_t len)
> @@ -186,7 +192,7 @@ static ssize_t tsm_report_service_manifest_version_store(struct config_item *cfg
>  
>  	return len;
>  }
> -CONFIGFS_ATTR_WO(tsm_report_, service_manifest_version);
> +CONFIGFS_ATTR_VISIBLE_WO(tsm_report_, service_manifest_version, provider_visibility);
>  
>  static ssize_t tsm_report_inblob_write(struct config_item *cfg,
>  				       const void *buf, size_t count)
> @@ -333,7 +339,7 @@ static ssize_t tsm_report_manifestblob_read(struct config_item *cfg, void *buf,
>  
>  	return tsm_report_read(report, buf, count, TSM_MANIFEST);
>  }
> -CONFIGFS_BIN_ATTR_RO(tsm_report_, manifestblob, NULL, TSM_OUTBLOB_MAX);
> +CONFIGFS_BIN_ATTR_VISIBLE_RO(tsm_report_, manifestblob, NULL, TSM_OUTBLOB_MAX, provider_visibility);

Yeah the same callback specified multiple times feels like something
that should only happen once at the group level.