lkml.org 
[lkml]   [2020]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: x86/seves] x86/boot/compressed/64: Call set_sev_encryption_mask() earlier
The following commit has been merged into the x86/seves branch of tip:

Commit-ID: c2a0304a286f386e45cea3f4b0617f0813de67fd
Gitweb: https://git.kernel.org/tip/c2a0304a286f386e45cea3f4b0617f0813de67fd
Author: Joerg Roedel <jroedel@suse.de>
AuthorDate: Mon, 07 Sep 2020 15:15:21 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Mon, 07 Sep 2020 19:45:25 +02:00

x86/boot/compressed/64: Call set_sev_encryption_mask() earlier

Call set_sev_encryption_mask() while still on the stage 1 #VC-handler
because the stage 2 handler needs the kernel's own page tables to be
set up, to which calling set_sev_encryption_mask() is a prerequisite.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-21-joro@8bytes.org
---
arch/x86/boot/compressed/head_64.S | 9 ++++++++-
arch/x86/boot/compressed/ident_map_64.c | 3 ---
2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index fb6c039..42190c0 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -543,9 +543,16 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)
rep stosq

/*
- * Load stage2 IDT and switch to our own page-table
+ * If running as an SEV guest, the encryption mask is required in the
+ * page-table setup code below. When the guest also has SEV-ES enabled
+ * set_sev_encryption_mask() will cause #VC exceptions, but the stage2
+ * handler can't map its GHCB because the page-table is not set up yet.
+ * So set up the encryption mask here while still on the stage1 #VC
+ * handler. Then load stage2 IDT and switch to the kernel's own
+ * page-table.
*/
pushq %rsi
+ call set_sev_encryption_mask
call load_stage2_idt
call initialize_identity_maps
popq %rsi
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index 62e42c1..b4f2a5f 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -105,9 +105,6 @@ static void add_identity_map(unsigned long start, unsigned long end)
/* Locates and clears a region for a new top level page table. */
void initialize_identity_maps(void)
{
- /* If running as an SEV guest, the encryption mask is required. */
- set_sev_encryption_mask();
-
/* Exclude the encryption mask from __PHYSICAL_MASK */
physical_mask &= ~sme_me_mask;

\
 
 \ /
  Last update: 2020-09-10 11:35    [W:0.694 / U:0.236 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site