Merge branch 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x865 kdump updates from Thomas Gleixner:
 "Yet more kexec/kdump updates:

   - Properly support kexec when AMD's memory encryption (SME) is
     enabled

   - Pass reserved e820 ranges to the kexec kernel so both PCI and SME
     can work"

* 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  fs/proc/vmcore: Enable dumping of encrypted memory when SEV was active
  x86/kexec: Set the C-bit in the identity map page table when SEV is active
  x86/kexec: Do not map kexec area as decrypted when SEV is active
  x86/crash: Add e820 reserved ranges to kdump kernel's e820 table
  x86/mm: Rework ioremap resource mapping determination
  x86/e820, ioport: Add a new I/O resource descriptor IORES_DESC_RESERVED
  x86/mm: Create a workarea in the kernel for SME early encryption
  x86/mm: Identify the end of the kernel area to be reserved

1 files changed, 28 insertions, 3 deletions

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 9184037aec62..5dcd438ad8f2 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -123,12 +123,13 @@ static void free_transition_pgtable(struct kimage *image)
 
 static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
 {
+	pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
+	unsigned long vaddr, paddr;
+	int result = -ENOMEM;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
-	unsigned long vaddr, paddr;
-	int result = -ENOMEM;
 
 	vaddr = (unsigned long)relocate_kernel;
 	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
@@ -165,7 +166,11 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
 		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
 	}
 	pte = pte_offset_kernel(pmd, vaddr);
-	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC_NOENC));
+
+	if (sev_active())
+		prot = PAGE_KERNEL_EXEC;
+
+	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
 	return 0;
 err:
 	return result;
@@ -202,6 +207,11 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 	level4p = (pgd_t *)__va(start_pgtable);
 	clear_page(level4p);
 
+	if (sev_active()) {
+		info.page_flag   |= _PAGE_ENC;
+		info.kernpg_flag |= _PAGE_ENC;
+	}
+
 	if (direct_gbpages)
 		info.direct_gbpages = true;
 
@@ -644,8 +654,20 @@ void arch_kexec_unprotect_crashkres(void)
 	kexec_mark_crashkres(false);
 }
 
+/*
+ * During a traditional boot under SME, SME will encrypt the kernel,
+ * so the SME kexec kernel also needs to be un-encrypted in order to
+ * replicate a normal SME boot.
+ *
+ * During a traditional boot under SEV, the kernel has already been
+ * loaded encrypted, so the SEV kexec kernel needs to be encrypted in
+ * order to replicate a normal SEV boot.
+ */
 int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
 {
+	if (sev_active())
+		return 0;
+
 	/*
 	 * If SME is active we need to be sure that kexec pages are
 	 * not encrypted because when we boot to the new kernel the
@@ -656,6 +678,9 @@ int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
 
 void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
 {
+	if (sev_active())
+		return;
+
 	/*
 	 * If SME is active we need to reset the pages back to being
 	 * an encrypted mapping before freeing them.