linux-kernel - Re: [PATCH v6 07/10] x86/virt/tdx: Trim away tail null CMRs

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Message-ID: <67200c325bebc_bc69d29459@dwillia2-xfh.jf.intel.com.notmuch>
Date: Mon, 28 Oct 2024 15:12:02 -0700
From: Dan Williams <dan.j.williams@...el.com>
To: Kai Huang <kai.huang@...el.com>, <dave.hansen@...el.com>,
	<kirill.shutemov@...ux.intel.com>, <tglx@...utronix.de>, <bp@...en8.de>,
	<peterz@...radead.org>, <mingo@...hat.com>, <hpa@...or.com>,
	<dan.j.williams@...el.com>, <seanjc@...gle.com>, <pbonzini@...hat.com>
CC: <x86@...nel.org>, <linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>,
	<rick.p.edgecombe@...el.com>, <isaku.yamahata@...el.com>,
	<adrian.hunter@...el.com>, <nik.borisov@...e.com>, <kai.huang@...el.com>
Subject: Re: [PATCH v6 07/10] x86/virt/tdx: Trim away tail null CMRs

Kai Huang wrote:
> TDX architecturally supports up to 32 CMRs.  The global metadata field
> "NUM_CMRS" reports the number of CMR entries that can be read by the
> kernel.  However, that field may just report the maximum number of CMRs
> albeit the actual number of CMRs is smaller, in which case there are
> tail null CMRs (size is 0).
> 
> Trim away those null CMRs, and print valid CMRs since they are useful
> at least to developers.
> 
> More information about CMR can be found at "Intel TDX ISA Background:
> Convertible Memory Ranges (CMRs)" in TDX 1.5 base spec [1], and
> "CMR_INFO" in TDX 1.5 ABI spec [2].
> 
> Now get_tdx_sys_info() just reads kernel-needed global metadata to
> kernel structure, and it is auto-generated.  Add a wrapper function
> init_tdx_sys_info() to invoke get_tdx_sys_info() and provide room to do
> additional things like dealing with CMRs.
> 
> Link: https://cdrdv2.intel.com/v1/dl/getContent/733575 [1]
> Link: https://cdrdv2.intel.com/v1/dl/getContent/733579 [2]
> Signed-off-by: Kai Huang <kai.huang@...el.com>

Looks good to me:

Reviewed-by: Dan Williams <dan.j.williams@...el.com>