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From: James Bottomley <jejb@linux.ibm.com>
To: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>,
	"Yao, Jiewen" <jiewen.yao@intel.com>,
	"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>
Cc: Claudio Siqueira de Carvalho <cclaudio@ibm.com>,
	Joerg Roedel <jroedel@suse.com>,
	"Lange, Jon" <jlange@microsoft.com>,
	"Dong, Eddie" <eddie.dong@intel.com>,
	"Johnson, Simon P" <simon.p.johnson@intel.com>,
	"Reshetova, Elena" <elena.reshetova@intel.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>
Subject: Re: question on vTPM interface in coconut-svsm
Date: Thu, 28 Mar 2024 08:33:05 -0400	[thread overview]
Message-ID: <f450d9b8c427a7d3c5ac53882d004280fc9b945a.camel@linux.ibm.com> (raw)
In-Reply-To: <8c389411-c547-488f-93d2-ac953e212eaf@linux.microsoft.com>

On Thu, 2024-03-28 at 13:22 +0100, Jeremi Piotrowski wrote:
[...]
> Azure ships the configuration described above for SEV-SNP (and TDX).
> The TPM is implemented in an "SVSM"(paravisor), exposed through TPM
> CRB MMIO. The kernel has a callback informing ioremap which MMIO
> addresses should be considered shared/private [1]. This is the Hyper-
> v implementation of that callback: [2].
> 
> So it can work if you detect it like this:
> 
> if (SEV_SNP_GUEST && SVSM_PRESENT && SVSM_PROVIDES_VTPM)
>    // vtpm should be mapped private

Well, yes, it's pretty much identical to the detection mechanism used
to activate the platform TPM driver:

https://lore.kernel.org/all/83bcfc398d885f9e42d5aae42359fe02ab12d306.camel@linux.ibm.com/

The SVSM_PROVIDES_VTPM is actually a dynamic probe to find the vTPM
protocol inside the SVSM.

So what's the mechanism hyper-v uses to start a CRB command?

James


  reply	other threads:[~2024-03-28 12:35 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <MW4PR11MB5872CE9BEF8361203F72EDFD8C3B2@MW4PR11MB5872.namprd11.prod.outlook.com>
2024-03-28  6:29 ` question on vTPM interface in coconut-svsm Yao, Jiewen
2024-03-28  8:11   ` Reshetova, Elena
2024-03-28  9:11     ` Joerg Roedel
2024-03-28 12:03   ` James Bottomley
2024-03-28 12:22     ` Jeremi Piotrowski
2024-03-28 12:33       ` James Bottomley [this message]
2024-03-28 13:41         ` Jeremi Piotrowski
2024-03-28 13:54           ` James Bottomley
2024-03-28 14:09             ` Jeremi Piotrowski
2024-07-04  3:07             ` Coconut-SVSM - vTPM support for Intel TD Partitioning Yao, Jiewen
2024-08-01 22:38               ` Yao, Jiewen
2024-08-02  5:23                 ` Dionna Amalie Glaze
2024-08-02 10:02                   ` Yao, Jiewen
2024-08-02 12:27                 ` James Bottomley
2024-08-02 15:40                 ` James Bottomley
2024-08-03  1:54                   ` Dionna Amalie Glaze
2024-08-03  2:19                     ` James Bottomley
2024-08-05  9:55                       ` Reshetova, Elena
2024-08-05 15:21                         ` James Bottomley
2024-08-06  8:21                           ` Reshetova, Elena
2024-08-06 15:51                             ` Claudio Siqueira de Carvalho
2024-08-06 16:23                               ` James Bottomley
2024-08-07 11:28                                 ` Reshetova, Elena
2024-08-07 12:21                                   ` James Bottomley
2024-08-07 16:04                                     ` Reshetova, Elena
2024-08-16  3:38                                       ` Yao, Jiewen
2024-08-16 16:13                                         ` Dionna Amalie Glaze
2024-08-19  5:54                                           ` Yao, Jiewen
2024-08-06 16:19                             ` James Bottomley
2024-08-07  8:46                               ` Reshetova, Elena
2024-08-16  3:09                                 ` Yao, Jiewen
2024-08-16  3:27                   ` Yao, Jiewen
2024-04-08  8:50   ` question on vTPM interface in coconut-svsm Joerg Roedel
2024-04-08 15:05     ` Yao, Jiewen

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