kexec: Allocate decrypted control pages for kdump if SME is enabled

When SME is enabled in the first kernel, it needs to allocate decrypted
pages for kdump because when the kdump kernel boots, these pages need to
be accessed decrypted in the initial boot stage, before SME is enabled.

 [ bp: clean up text. ]

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: jroedel@suse.de
Link: https://lkml.kernel.org/r/20180930031033.22110-3-lijiang@redhat.com

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 23a83a4da38a1dffc5203c828a384531b6cce9b2..86ef06d3dbe3a067ee00fe31c924b11be7340d31 100644 (file)
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -471,6 +471,10 @@ static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
                }
        }
 
+       /* Ensure that these pages are decrypted if SME is enabled. */
+       if (pages)
+               arch_kexec_post_alloc_pages(page_address(pages), 1 << order, 0);
+
        return pages;
 }
 
@@ -867,6 +871,7 @@ 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 +889,7 @@ 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;