linux-kernel - [PATCH 2/3] kexec: Set the C-bit in the identity map page table when SEV is active

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190315103203.13128-3-lijiang@redhat.com>
Date:   Fri, 15 Mar 2019 18:32:02 +0800
From:   Lianbo Jiang <lijiang@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     kexec@...ts.infradead.org, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, x86@...nel.org, hpa@...or.com,
        akpm@...ux-foundation.org, dyoung@...hat.com,
        brijesh.singh@....com, thomas.lendacky@....com, bhe@...hat.com
Subject: [PATCH 2/3] kexec: Set the C-bit in the identity map page table when SEV is active

When SEV is active, the second kernel image is loaded into the
encrypted memory. Lets make sure that when kexec builds the
identity mapping page table it adds the memory encryption mask(C-bit).

Co-developed-by: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
---
 arch/x86/kernel/machine_kexec_64.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index bcebf4993da4..8c58d1864500 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -56,6 +56,7 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
 	pte_t *pte;
 	unsigned long vaddr, paddr;
 	int result = -ENOMEM;
+	pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
 
 	vaddr = (unsigned long)relocate_kernel;
 	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
@@ -92,7 +93,11 @@ 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;
@@ -129,6 +134,11 @@ 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 = _KERNPG_TABLE;
+	}
+
 	if (direct_gbpages)
 		info.direct_gbpages = true;
 
-- 
2.17.1