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From: Dexuan Cui <decui@microsoft.com>
To: Dave Hansen <dave.hansen@intel.com>,
	"ak@linux.intel.com" <ak@linux.intel.com>,
	"arnd@arndb.de" <arnd@arndb.de>, "bp@alien8.de" <bp@alien8.de>,
	"brijesh.singh@amd.com" <brijesh.singh@amd.com>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"jane.chu@oracle.com" <jane.chu@oracle.com>,
	"kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>,
	KY Srinivasan <kys@microsoft.com>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
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	"sathyanarayanan.kuppuswamy@linux.intel.com" 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
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	"x86@kernel.org" <x86@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 1/6] x86/tdx: Support hypercalls for TDX guests on Hyper-V
Date: Wed, 23 Nov 2022 01:37:26 +0000	[thread overview]
Message-ID: <SA1PR21MB13353C24B5BF2E7D6E8BCFA5BF0C9@SA1PR21MB1335.namprd21.prod.outlook.com> (raw)
In-Reply-To: <18323d11-146f-c418-e8f0-addb2b8adb19@intel.com>

> From: Dave Hansen <dave.hansen@intel.com>
> Sent: Monday, November 21, 2022 12:39 PM
> [...]
> On 11/21/22 11:51, Dexuan Cui wrote:
> > __tdx_hypercall() doesn't work for a TDX guest running on Hyper-V,
> > because Hyper-V uses a different calling convention, so add the
> > new function __tdx_ms_hv_hypercall().
> 
> Other than R10 being variable here and fixed for __tdx_hypercall(), this
> looks *EXACTLY* the same as __tdx_hypercall(), or at least a strict
> subset of what __tdx_hypercall() can do.
> 
> Did I miss something?

The existing asm code for __tdx_hypercall() passes through R10~R15
(see TDVMCALL_EXPOSE_REGS_MASK) to the (KVM) hypervisor.

Unluckily, for Hyper-V, we need to pass through RDX, R8, R10 and R11
to Hyper-V, so I don't think I can use the existing __tdx_hypercall() ?

> Another way of saying this:  It seems like you could do this with a new
> version of _tdx_hypercall() (and all in C) instead of a new
> __tdx_hypercall().

I don't think the current TDVMCALL_EXPOSE_REGS_MASK allows me
to pass through RDX and R8 to Hyper-V.

PS, the comment before __tdx_hypercall() contains this line:

"* RBX, RBP, RDI, RSI  - Used to pass VMCALL sub function specific
arguments."

But it looks like currently RBX an RBP are not used at all in 
arch/x86/coco/tdx/tdcall.S ?


  parent reply	other threads:[~2022-11-23  1:37 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-21 19:51 [PATCH 0/6] Support TDX guests on Hyper-V Dexuan Cui
2022-11-21 19:51 ` [PATCH 1/6] x86/tdx: Support hypercalls for " Dexuan Cui
2022-11-21 20:38   ` Dave Hansen
2022-11-21 23:52     ` Kirill A. Shutemov
2022-11-23  1:37     ` Dexuan Cui [this message]
2022-11-23  1:56       ` Dexuan Cui
2022-11-23 16:04         ` Dave Hansen
2022-11-23 18:59           ` Dexuan Cui
2022-11-23  3:52       ` Sathyanarayanan Kuppuswamy
2022-11-23 14:40       ` Kirill A. Shutemov
2022-11-23 18:55         ` Dexuan Cui
2022-11-30 19:14           ` Dexuan Cui
2022-12-02 21:47             ` 'Kirill A. Shutemov'
2022-11-23 16:03       ` Dave Hansen
2022-11-21 19:51 ` [PATCH 2/6] x86/tdx: Retry TDVMCALL_MAP_GPA() when needed Dexuan Cui
2022-11-21 20:55   ` Dave Hansen
2022-11-23  2:55     ` Dexuan Cui
2022-11-22  0:01   ` Kirill A. Shutemov
2022-11-23  3:27     ` Dexuan Cui
2022-11-23 13:30       ` Michael Kelley (LINUX)
2022-11-28  0:07         ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 3/6] x86/tdx: Support vmalloc() for tdx_enc_status_changed() Dexuan Cui
2022-11-21 21:00   ` Dave Hansen
2022-11-23  4:01     ` Dexuan Cui
2022-11-22  0:24   ` Kirill A. Shutemov
2022-11-23 23:51     ` Dexuan Cui
2022-11-24  7:51       ` Kirill A. Shutemov
2022-11-27 20:27         ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 4/6] x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests Dexuan Cui
2022-11-21 21:01   ` Dave Hansen
2022-11-21 21:48     ` Borislav Petkov
2022-11-22  0:32   ` Sathyanarayanan Kuppuswamy
2022-11-23 19:13     ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 5/6] x86/hyperv: Support hypercalls for " Dexuan Cui
2022-11-21 20:05   ` Dave Hansen
2022-11-23  2:14     ` Dexuan Cui
2022-11-23 14:47       ` Kirill A. Shutemov
2022-11-23 18:13         ` Dexuan Cui
2022-11-23 18:18         ` Sathyanarayanan Kuppuswamy
2022-11-23 19:07           ` Dexuan Cui
2022-11-23 14:45   ` Michael Kelley (LINUX)
2022-11-28  0:58     ` Dexuan Cui
2022-11-28  1:20       ` Michael Kelley (LINUX)
2022-11-28  1:36         ` Dexuan Cui
2022-11-28  1:21       ` Sathyanarayanan Kuppuswamy
2022-11-28  1:55         ` Dexuan Cui
2022-11-28 15:22       ` Dave Hansen
2022-11-28 19:03         ` Dexuan Cui
2022-11-28 19:11           ` Dave Hansen
2022-11-28 19:37             ` Dexuan Cui
2022-11-28 19:48               ` Dave Hansen
2022-11-28 20:36                 ` Dexuan Cui
2022-11-28 21:15                   ` Dave Hansen
2022-11-28 21:53                     ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 6/6] Drivers: hv: vmbus: Support " Dexuan Cui
2023-01-06 11:00   ` Zhi Wang
2023-01-09  6:59     ` Dexuan Cui

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