Re: [PATCH] x86/tdx: Optimize try_accept_memory() to reduce 1GB page accepted failed times

From: kernel test robot
Date: Tue Jan 09 2024 - 18:47:29 EST


Hi Jun,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/x86/tdx]
[also build test WARNING on next-20240109]
[cannot apply to linus/master v6.7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Jun-Miao/x86-tdx-Optimize-try_accept_memory-to-reduce-1GB-page-accepted-failed-times/20240109-134908
base: tip/x86/tdx
patch link: https://lore.kernel.org/r/20240109054824.9023-1-jun.miao%40intel.com
patch subject: [PATCH] x86/tdx: Optimize try_accept_memory() to reduce 1GB page accepted failed times
config: x86_64-rhel-8.3-bpf (https://download.01.org/0day-ci/archive/20240110/202401100747.8LTktRbX-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240110/202401100747.8LTktRbX-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401100747.8LTktRbX-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

arch/x86/coco/tdx/tdx-shared.c: In function 'tdx_accept_memory':
>> arch/x86/coco/tdx/tdx-shared.c:62:17: warning: "/*" within comment [-Wcomment]
62 | /* The 4KB page case or accept 2MB page failed case. */
|


vim +62 arch/x86/coco/tdx/tdx-shared.c

40
41 bool tdx_accept_memory(phys_addr_t start, phys_addr_t end)
42 {
43 /*
44 * For shared->private conversion, accept the page using
45 * TDG_MEM_PAGE_ACCEPT TDX module call.
46 */
47 while (start < end) {
48 unsigned long len = end - start;
49 unsigned long accept_size;
50
51 /*
52 * Try larger accepts first. It gives chance to VMM to keep
53 * 1G/2M Secure EPT entries where possible and speeds up
54 * process by cutting number of hypercalls (if successful).
55 * Since per current TDX spec, only support for adding 4KB or
56 * 2MB page dynamically.
57 * /
58
59 if (IS_ALIGNED(start, PMD_SIZE) && len >= PMD_SIZE)
60 accept_size = try_accept_one(start, len, PG_LEVEL_2M);
61
> 62 /* The 4KB page case or accept 2MB page failed case. */
63 if (!accept_size)
64 accept_size = try_accept_one(start, len, PG_LEVEL_4K);
65 if (!accept_size)
66 return false;
67 start += accept_size;
68 }
69
70 return true;
71 }
72

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