The decompressed kernel initially relies on the identity map set up by
the boot/compressed kernel for accessing things like boot_params. With
the recent introduction of SEV-SNP support, the decompressed kernel
also needs to access the setup_data entries pointed to by
boot_params->hdr.setup_data. This can lead to a crash during early boot
due to these entries not currently being included in the initial
identity map.
Fix this by including mappings for the setup_data entries in the
initial identity map.
Fixes: b190a043c49a ("x86/sev: Add SEV-SNP feature detection/setup")
Reported-by: Jun'ichi Nomura <junichi.nomura@xxxxxxx>
Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
---
arch/x86/boot/compressed/ident_map_64.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index 44c350d627c7..e2249ec93229 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -110,6 +110,7 @@ void kernel_add_identity_map(unsigned long start, unsigned long end)
void initialize_identity_maps(void *rmode)
{
unsigned long cmdline;
+ struct setup_data *sd;
/* Exclude the encryption mask from __PHYSICAL_MASK */
physical_mask &= ~sme_me_mask;
@@ -163,6 +164,17 @@ void initialize_identity_maps(void *rmode)
cmdline = get_cmd_line_ptr();
kernel_add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);
+ /*
+ * Also map the setup_data entries passed via boot_params in case they
+ * need to be accessed by uncompressed kernel via the identity mapping.
+ */
+ sd = (struct setup_data *)boot_params->hdr.setup_data;
+ while (sd) {
+ kernel_add_identity_map((unsigned long)sd,
+ (unsigned long)sd + sizeof(*sd) + sd->len);
+ sd = (struct setup_data *)sd->next;
+ }
+
sev_prep_identity_maps(top_level_pgt);
/* Load the new page-table. */
--
2.25.1
