[PATCH 19/70] x86/boot/compressed/64: Call set_sev_encryption_mask earlier

Joerg Roedel
2020-03-19T09:19:34Z

From: Joerg Roedel <jroedel@suse.de>

Call set_sev_encryption_mask() while still on the stage 1 #VC-handler,
because the stage 2 handler needs our 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>
---
arch/x86/boot/compressed/head_64.S | 8 +++++++-
arch/x86/boot/compressed/ident_map_64.c | 3 ---
2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 5164d2e8631a..fdebbfafe5a2 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -491,9 +491,15 @@ 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 our 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 ba5b88189220..5b720736a789 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -107,9 +107,6 @@ 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;

--
2.17.1