SEV-ES/SNP guest uses GHCB page to communicate with the host. Such a
page should remain unencrypted (its C-bit should be unset in the guest page
table). Therefore, call setup_ghcb_pte() in the path of setup_vm() to ensure
C-bit of GHCB's pte is unset, for a new page table that will be setup as
a part of page allocation for UEFI-based SEV-ES/SNP tests later on.
Signed-off-by: Pavan Kumar Paluri <papaluri@xxxxxxx>
---
lib/x86/vm.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/x86/vm.c b/lib/x86/vm.c
index 90f73fbb2dfd..ce2063aee75d 100644
--- a/lib/x86/vm.c
+++ b/lib/x86/vm.c
@@ -3,6 +3,7 @@
#include "vmalloc.h"
#include "alloc_page.h"
#include "smp.h"
+#include "amd_sev.h"
static pteval_t pte_opt_mask;
@@ -197,6 +198,11 @@ void *setup_mmu(phys_addr_t end_of_memory, void *opt_mask)
init_alloc_vpage((void*)(3ul << 30));
#endif
+#ifdef CONFIG_EFI
+ if (amd_sev_es_enabled())
+ setup_ghcb_pte(cr3);
+#endif
+
write_cr3(virt_to_phys(cr3));
#ifndef __x86_64__
write_cr4(X86_CR4_PSE);
--
2.34.1
