@@ -12,6 +12,7 @@
*/
#include "misc.h"
+#include <asm/pgtable_types.h>
#include <asm/sev-es.h>
#include <asm/trapnr.h>
#include <asm/trap_pf.h>
@@ -85,11 +85,13 @@ extern void sev_es_ist_enter(struct pt_regs *regs);
extern void sev_es_ist_exit(void);
extern int sev_es_setup_ap_jump_table(struct real_mode_header *rmh);
extern void sev_es_nmi_complete(void);
+extern int __init sev_es_efi_map_ghcbs(pgd_t *pgd);
#else
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
static inline void sev_es_ist_exit(void) { }
static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { return 0; }
static inline void sev_es_nmi_complete(void) { }
+static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; }
#endif
#endif
@@ -507,6 +507,36 @@ int sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
return 0;
}
+/*
+ * This is needed by the OVMF UEFI firmware which will use whatever it finds in
+ * the GHCB MSR as its GHCB to talk to the hypervisor. So make sure the per-cpu
+ * runtime GHCBs used by the kernel are also mapped in the EFI page-table.
+ */
+int __init sev_es_efi_map_ghcbs(pgd_t *pgd)
+{
+ struct sev_es_runtime_data *data;
+ unsigned long address, pflags;
+ int cpu;
+ u64 pfn;
+
+ if (!sev_es_active())
+ return 0;
+
+ pflags = _PAGE_NX | _PAGE_RW;
+
+ for_each_possible_cpu(cpu) {
+ data = per_cpu(runtime_data, cpu);
+
+ address = __pa(&data->ghcb_page);
+ pfn = address >> PAGE_SHIFT;
+
+ if (kernel_map_pages_in_pgd(pgd, pfn, address, 1, pflags))
+ return 1;
+ }
+
+ return 0;
+}
+
static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
{
struct pt_regs *regs = ctxt->regs;
@@ -47,6 +47,7 @@
#include <asm/realmode.h>
#include <asm/time.h>
#include <asm/pgalloc.h>
+#include <asm/sev-es.h>
/*
* We allocate runtime services regions top-down, starting from -4G, i.e.
@@ -238,6 +239,15 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
return 1;
}
+ /*
+ * When SEV-ES is active, the GHCB as set by the kernel will be used
+ * by firmware. Create a 1:1 unencrypted mapping for each GHCB.
+ */
+ if (sev_es_efi_map_ghcbs(pgd)) {
+ pr_err("Failed to create 1:1 mapping for the GHCBs!\n");
+ return 1;
+ }
+
/*
* When making calls to the firmware everything needs to be 1:1
* mapped and addressable with 32-bit pointers. Map the kernel