From: Kai Huang <kai.huang@intel.com>
To: Dave Hansen <dave.hansen@intel.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: seanjc@google.com, pbonzini@redhat.com, len.brown@intel.com,
tony.luck@intel.com, rafael.j.wysocki@intel.com,
reinette.chatre@intel.com, dan.j.williams@intel.com,
peterz@infradead.org, ak@linux.intel.com,
kirill.shutemov@linux.intel.com,
sathyanarayanan.kuppuswamy@linux.intel.com,
isaku.yamahata@intel.com
Subject: Re: [PATCH v5 12/22] x86/virt/tdx: Convert all memory regions in memblock to TDX memory
Date: Thu, 07 Jul 2022 14:37:46 +1200 [thread overview]
Message-ID: <202a463dd5443ccf2dc502e496e7d45ba5f05440.camel@intel.com> (raw)
In-Reply-To: <76d7604ff21b26252733165478d5c54035d84d98.camel@intel.com>
> > > +/*
> > > + * Walks over all memblock memory regions that are intended to be
> > > + * converted to TDX memory. Essentially, it is all memblock memory
> > > + * regions excluding the low memory below 1MB.
> > > + *
> > > + * This is because on some TDX platforms the low memory below 1MB is
> > > + * not included in CMRs. Excluding the low 1MB can still guarantee
> > > + * that the pages managed by the page allocator are always TDX memory,
> > > + * as the low 1MB is reserved during kernel boot and won't end up to
> > > + * the ZONE_DMA (see reserve_real_mode()).
> > > + */
> > > +#define memblock_for_each_tdx_mem_pfn_range(i, p_start, p_end, p_nid) \
> > > + for_each_mem_pfn_range(i, MAX_NUMNODES, p_start, p_end, p_nid) \
> > > + if (!pfn_range_skip_lowmem(p_start, p_end))
> >
> > Let's summarize where we are at this point:
> >
> > 1. All RAM is described in memblocks
> > 2. Some memblocks are reserved and some are free
> > 3. The lower 1MB is marked reserved
> > 4. for_each_mem_pfn_range() walks all reserved and free memblocks, so we
> > have to exclude the lower 1MB as a special case.
> >
> > That seems superficially rather ridiculous. Shouldn't we just pick a
> > memblock iterator that skips the 1MB? Surely there is such a thing.
>
> Perhaps you are suggesting we should always loop the _free_ ranges so we don't
> need to care about the first 1MB which is reserved?
>
> The problem is some reserved memory regions are actually later freed to the page
> allocator, for example, initrd. So to cover all those 'late-freed-reserved-
> regions', I used for_each_mem_pfn_range(), instead of for_each_free_mem_range().
>
> Btw, I do have a checkpatch warning around this code:
>
> ERROR: Macros with complex values should be enclosed in parentheses
> #109: FILE: arch/x86/virt/vmx/tdx/tdx.c:377:
> +#define memblock_for_each_tdx_mem_pfn_range(i, p_start, p_end, p_nid) \
> + for_each_mem_pfn_range(i, MAX_NUMNODES, p_start, p_end, p_nid) \
> + if (!pfn_range_skip_lowmem(p_start, p_end))
>
> But it looks like a false positive to me.
Hi Dave,
Sorry to ping. Just double check, any comments around here, ..
>
> > Or, should we be doing something different with the 1MB in the memblock
> > structure?
>
> memblock APIs are used by other kernel components. I don't think we should
> modify memblock code behaviour for TDX. Do you have any specific suggestion?
>
> One possible option I can think is explicitly "register" memory regions as TDX
> memory when they are firstly freed to the page allocator.
[...]
>
> This will require new data structures to represent TDX memblock and the code to
> create, insert and merge contiguous TDX memblocks, etc. The advantage is we can
> just iterate those TDX memblocks when constructing TDMRs.
>
>
And here?
next prev parent reply other threads:[~2022-07-07 2:44 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-22 11:15 [PATCH v5 00/22] TDX host kernel support Kai Huang
2022-06-22 11:15 ` [PATCH v5 01/22] x86/virt/tdx: Detect TDX during kernel boot Kai Huang
2022-06-23 5:57 ` Chao Gao
2022-06-23 9:23 ` Kai Huang
2022-08-02 2:01 ` [PATCH v5 1/22] " Wu, Binbin
2022-08-03 9:25 ` Kai Huang
2022-06-22 11:15 ` [PATCH v5 02/22] cc_platform: Add new attribute to prevent ACPI CPU hotplug Kai Huang
2022-06-22 11:42 ` Rafael J. Wysocki
2022-06-23 0:01 ` Kai Huang
2022-06-27 8:01 ` Igor Mammedov
2022-06-28 10:04 ` Kai Huang
2022-06-28 11:52 ` Igor Mammedov
2022-06-28 17:33 ` Rafael J. Wysocki
2022-06-28 23:41 ` Kai Huang
2022-06-24 18:57 ` Dave Hansen
2022-06-27 5:05 ` Kai Huang
2022-07-13 11:09 ` Kai Huang
2022-07-19 17:46 ` Dave Hansen
2022-07-19 23:54 ` Kai Huang
2022-08-03 3:40 ` Binbin Wu
2022-08-03 9:20 ` Kai Huang
2022-06-29 5:33 ` Christoph Hellwig
2022-06-29 9:09 ` Kai Huang
2022-08-03 3:55 ` Binbin Wu
2022-08-03 9:21 ` Kai Huang
2022-06-22 11:15 ` [PATCH v5 03/22] cc_platform: Add new attribute to prevent ACPI memory hotplug Kai Huang
2022-06-22 11:45 ` Rafael J. Wysocki
2022-06-23 0:08 ` Kai Huang
2022-06-28 17:55 ` Rafael J. Wysocki
2022-06-28 12:01 ` Igor Mammedov
2022-06-28 23:49 ` Kai Huang
2022-06-29 8:48 ` Igor Mammedov
2022-06-29 9:13 ` Kai Huang
2022-06-22 11:16 ` [PATCH v5 04/22] x86/virt/tdx: Prevent ACPI CPU hotplug and " Kai Huang
2022-06-24 1:41 ` Chao Gao
2022-06-24 11:21 ` Kai Huang
2022-06-29 8:35 ` Yuan Yao
2022-06-29 9:17 ` Kai Huang
2022-06-29 14:22 ` Dave Hansen
2022-06-29 23:02 ` Kai Huang
2022-06-30 15:44 ` Dave Hansen
2022-06-30 22:45 ` Kai Huang
2022-06-22 11:16 ` [PATCH v5 05/22] x86/virt/tdx: Prevent hot-add driver managed memory Kai Huang
2022-06-24 2:12 ` Chao Gao
2022-06-24 11:23 ` Kai Huang
2022-06-24 19:01 ` Dave Hansen
2022-06-27 5:27 ` Kai Huang
2022-06-22 11:16 ` [PATCH v5 06/22] x86/virt/tdx: Add skeleton to initialize TDX on demand Kai Huang
2022-06-24 2:39 ` Chao Gao
2022-06-24 11:27 ` Kai Huang
2022-06-22 11:16 ` [PATCH v5 07/22] x86/virt/tdx: Implement SEAMCALL function Kai Huang
2022-06-24 18:38 ` Dave Hansen
2022-06-27 5:23 ` Kai Huang
2022-06-27 20:58 ` Dave Hansen
2022-06-27 22:10 ` Kai Huang
2022-07-19 19:39 ` Dan Williams
2022-07-19 23:28 ` Kai Huang
2022-07-20 10:18 ` Kai Huang
2022-07-20 16:48 ` Dave Hansen
2022-07-21 1:52 ` Kai Huang
2022-07-27 0:34 ` Kai Huang
2022-07-27 0:50 ` Dave Hansen
2022-07-27 12:46 ` Kai Huang
2022-08-03 2:37 ` Kai Huang
2022-08-03 14:20 ` Dave Hansen
2022-08-03 22:35 ` Kai Huang
2022-08-04 10:06 ` Kai Huang
2022-06-22 11:16 ` [PATCH v5 08/22] x86/virt/tdx: Shut down TDX module in case of error Kai Huang
2022-06-24 18:50 ` Dave Hansen
2022-06-27 5:26 ` Kai Huang
2022-06-27 20:46 ` Dave Hansen
2022-06-27 22:34 ` Kai Huang
2022-06-27 22:56 ` Dave Hansen
2022-06-27 23:59 ` Kai Huang
2022-06-28 0:03 ` Dave Hansen
2022-06-28 0:11 ` Kai Huang
2022-06-22 11:16 ` [PATCH v5 09/22] x86/virt/tdx: Detect TDX module by doing module global initialization Kai Huang
2022-06-22 11:16 ` [PATCH v5 10/22] x86/virt/tdx: Do logical-cpu scope TDX module initialization Kai Huang
2022-06-22 11:17 ` [PATCH v5 11/22] x86/virt/tdx: Get information about TDX module and TDX-capable memory Kai Huang
2022-06-22 11:17 ` [PATCH v5 12/22] x86/virt/tdx: Convert all memory regions in memblock to TDX memory Kai Huang
2022-06-24 19:40 ` Dave Hansen
2022-06-27 6:16 ` Kai Huang
2022-07-07 2:37 ` Kai Huang [this message]
2022-07-07 14:26 ` Dave Hansen
2022-07-07 14:36 ` Juergen Gross
2022-07-07 23:42 ` Kai Huang
2022-07-07 23:34 ` Kai Huang
2022-08-03 1:30 ` Kai Huang
2022-08-03 14:22 ` Dave Hansen
2022-08-03 22:14 ` Kai Huang
2022-06-22 11:17 ` [PATCH v5 13/22] x86/virt/tdx: Add placeholder to construct TDMRs based on memblock Kai Huang
2022-06-22 11:17 ` [PATCH v5 14/22] x86/virt/tdx: Create TDMRs to cover all memblock memory regions Kai Huang
2022-06-22 11:17 ` [PATCH v5 15/22] x86/virt/tdx: Allocate and set up PAMTs for TDMRs Kai Huang
2022-06-24 20:13 ` Dave Hansen
2022-06-27 10:31 ` Kai Huang
2022-06-27 20:41 ` Dave Hansen
2022-06-27 22:50 ` Kai Huang
2022-06-27 22:57 ` Dave Hansen
2022-06-27 23:05 ` Kai Huang
2022-06-28 0:48 ` Xiaoyao Li
2022-06-28 17:03 ` Dave Hansen
2022-08-17 22:46 ` Sagi Shahar
2022-08-17 23:43 ` Huang, Kai
2022-06-22 11:17 ` [PATCH v5 16/22] x86/virt/tdx: Set up reserved areas for all TDMRs Kai Huang
2022-06-22 11:17 ` [PATCH v5 17/22] x86/virt/tdx: Reserve TDX module global KeyID Kai Huang
2022-06-22 11:17 ` [PATCH v5 18/22] x86/virt/tdx: Configure TDX module with TDMRs and " Kai Huang
2022-06-22 11:17 ` [PATCH v5 19/22] x86/virt/tdx: Configure global KeyID on all packages Kai Huang
2022-06-22 11:17 ` [PATCH v5 20/22] x86/virt/tdx: Initialize all TDMRs Kai Huang
2022-06-22 11:17 ` [PATCH v5 21/22] x86/virt/tdx: Support kexec() Kai Huang
2022-06-22 11:17 ` [PATCH v5 22/22] Documentation/x86: Add documentation for TDX host support Kai Huang
2022-08-18 4:07 ` Bagas Sanjaya
2022-08-18 9:33 ` Huang, Kai
2022-06-24 19:47 ` [PATCH v5 00/22] TDX host kernel support Dave Hansen
2022-06-27 4:09 ` Kai Huang
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