[PATCH v7 RESEND 2/4] kexec: allocate unencrypted control pages for kdump in case SME is enabled

[Lianbo Jiang]

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.

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.
+		 * By the way, it is unnecessary to call the arch_
+		 * kexec_pre_free_pages(), which will make the code
+		 * become more simple.
+		 */
+		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