From: Joerg Roedel <jroe...@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 <jroe...@suse.de>
Link: https://lore.kernel.org/r/20200724160336.5435-20-j...@8bytes.org
---
 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 013b29921836..c7fcf60cbd08 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -533,9 +533,15 @@ 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 62e42c11a336..b4f2a5f503cd 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;
 
-- 
2.28.0

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