On Thu, Sep 27, 2018 at 03:19:52PM +0800, Lianbo Jiang wrote:
> When SME is enabled in the first kernel, we will allocate unencrypted pages
> for kdump in order to be able to boot the kdump kernel like kexec.
This is not what the commit does - it marks the control pages as
decrypted when SME. Why doesn't the commit message state that and why is
this being done?
> Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx>
> Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
> kernel/kexec_core.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index 23a83a4da38a..e7efcd1a977b 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -471,6 +471,16 @@ static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
> }
> }
>
> + if (pages) {
> + /*
> + * For kdump, we need to ensure that these pages are
> + * unencrypted pages if SME is enabled.
Remember to always call unencrypted pages "decrypted" - this is the
convention we agreed upon and it should keep the confusion level at
minimum to others staring at this code.
> + * By the way, it is unnecessary to call the arch_
> + * kexec_pre_free_pages(), which will make the code
> + * become more simple.
> + */
This second sentence I don't understand...
> + arch_kexec_post_alloc_pages(page_address(pages), 1 << order, 0);
> + }
> return pages;
> }
>
> @@ -867,6 +877,7 @@ static int kimage_load_crash_segment(struct kimage *image,
> result = -ENOMEM;
> goto out;
> }
> + arch_kexec_post_alloc_pages(page_address(page), 1, 0);
> ptr = kmap(page);
> ptr += maddr & ~PAGE_MASK;
> mchunk = min_t(size_t, mbytes,
> @@ -884,6 +895,7 @@ static int kimage_load_crash_segment(struct kimage *image,
> result = copy_from_user(ptr, buf, uchunk);
> kexec_flush_icache_page(page);
> kunmap(page);
> + arch_kexec_pre_free_pages(page_address(page), 1);
> if (result) {
> result = -EFAULT;
> goto out;
> --
> 2.17.1
>
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
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