Re: [PATCH] ptp: kvm: Use decrypted memory in confidential guest on x86

[Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>]

On 21/02/2023 02:08, kernel test robot wrote:
> Hi Jeremi,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on horms-ipvs/master]
> [also build test WARNING on mst-vhost/linux-next net/master net-next/master linus/master v6.2]
> [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/Jeremi-Piotrowski/ptp-kvm-Use-decrypted-memory-in-confidential-guest-on-x86/20230220-210441
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/horms/ipvs.git master
> patch link:    https://lore.kernel.org/r/20230220130235.2603366-1-jpiotrowski%40linux.microsoft.com
> patch subject: [PATCH] ptp: kvm: Use decrypted memory in confidential guest on x86
> config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20230221/202302210943.Xq84rrhU-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
> reproduce (this is a W=1 build):
>         # https://github.com/intel-lab-lkp/linux/commit/0dd1701fd254692af3d0ca051e092e8dcef190c4
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Jeremi-Piotrowski/ptp-kvm-Use-decrypted-memory-in-confidential-guest-on-x86/20230220-210441
>         git checkout 0dd1701fd254692af3d0ca051e092e8dcef190c4
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         make W=1 O=build_dir ARCH=x86_64 olddefconfig
>         make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Link: https://lore.kernel.org/oe-kbuild-all/202302210943.Xq84rrhU-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>    drivers/ptp/ptp_kvm_x86.c: In function 'kvm_arch_ptp_init':
>    drivers/ptp/ptp_kvm_x86.c:63:9: error: implicit declaration of function 'kvm_arch_ptp_exit'; did you mean 'kvm_arch_ptp_init'? [-Werror=implicit-function-declaration]
>       63 |         kvm_arch_ptp_exit();
>          |         ^~~~~~~~~~~~~~~~~
>          |         kvm_arch_ptp_init
>    drivers/ptp/ptp_kvm_x86.c: At top level:
>>> drivers/ptp/ptp_kvm_x86.c:68:6: warning: no previous prototype for 'kvm_arch_ptp_exit' [-Wmissing-prototypes]
>       68 | void kvm_arch_ptp_exit(void)
>          |      ^~~~~~~~~~~~~~~~~
>>> drivers/ptp/ptp_kvm_x86.c:68:6: warning: conflicting types for 'kvm_arch_ptp_exit'; have 'void(void)'
>    drivers/ptp/ptp_kvm_x86.c:63:9: note: previous implicit declaration of 'kvm_arch_ptp_exit' with type 'void(void)'
>       63 |         kvm_arch_ptp_exit();
>          |         ^~~~~~~~~~~~~~~~~
>    cc1: some warnings being treated as errors
> 
> 
> vim +/kvm_arch_ptp_exit +68 drivers/ptp/ptp_kvm_x86.c
> 
>     67	
>   > 68	void kvm_arch_ptp_exit(void)
>     69	{
>     70		if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
>     71			WARN_ON(set_memory_encrypted((unsigned long)clock_pair, 1));
>     72			free_page((unsigned long)clock_pair);
>     73			clock_pair = NULL;
>     74		}
>     75	}
>     76	
> 

My bad - forgot to include changes to include/linux/ptp_kvm.h in the commit.
Will fix in v2, but will hold off a day or two in case someone has a suggestion
on how to reduce the allocation.

Jeremi