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Date:   Mon, 21 Nov 2022 12:38:36 -0800
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Subject: Re: [PATCH 1/6] x86/tdx: Support hypercalls for TDX guests on Hyper-V
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To:     Dexuan Cui <decui@microsoft.com>, ak@linux.intel.com,
        arnd@arndb.de, bp@alien8.de, brijesh.singh@amd.com,
        dan.j.williams@intel.com, dave.hansen@linux.intel.com,
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        kirill.shutemov@linux.intel.com, kys@microsoft.com,
        linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org,
        luto@kernel.org, mingo@redhat.com, peterz@infradead.org,
        rostedt@goodmis.org, sathyanarayanan.kuppuswamy@linux.intel.com,
        seanjc@google.com, tglx@linutronix.de, tony.luck@intel.com,
        wei.liu@kernel.org, x86@kernel.org
Cc:     linux-kernel@vger.kernel.org
References: <20221121195151.21812-1-decui@microsoft.com>
 <20221121195151.21812-2-decui@microsoft.com>
From:   Dave Hansen <dave.hansen@intel.com>
In-Reply-To: <20221121195151.21812-2-decui@microsoft.com>
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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?

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().