[PATCH v2 11/11] tpm_crb: support restoring older vmstate

[Joelle van Dyne <j@getutm.app>]

When we moved to a single mapping and modified TPM CRB's VMState, it
broke restoring of VMs that were saved on an older version. This
change allows those VMs to gracefully migrate to the new memory
mapping.

Signed-off-by: Joelle van Dyne <j@getutm.app>
---
 hw/tpm/tpm_crb.h        |  1 +
 hw/tpm/tpm_crb.c        | 14 ++++++++++++++
 hw/tpm/tpm_crb_common.c |  7 +++++++
 3 files changed, 22 insertions(+)

diff --git a/hw/tpm/tpm_crb.h b/hw/tpm/tpm_crb.h
index 7cdd37335f..7d8f643e98 100644
--- a/hw/tpm/tpm_crb.h
+++ b/hw/tpm/tpm_crb.h
@@ -70,5 +70,6 @@ enum TPMVersion tpm_crb_get_version(TPMCRBState *s);
 int tpm_crb_pre_save(TPMCRBState *s);
 void tpm_crb_reset(TPMCRBState *s, uint64_t baseaddr);
 void tpm_crb_init_memory(Object *obj, TPMCRBState *s, Error **errp);
+void tpm_crb_restore_regs(TPMCRBState *s, uint32_t *saved_regs);
 
 #endif /* TPM_TPM_CRB_H */
diff --git a/hw/tpm/tpm_crb.c b/hw/tpm/tpm_crb.c
index 594696ffb8..be29ca8c28 100644
--- a/hw/tpm/tpm_crb.c
+++ b/hw/tpm/tpm_crb.c
@@ -40,6 +40,7 @@ struct CRBState {
     ISADevice parent_obj;
 
     TPMCRBState state;
+    uint32_t legacy_regs[TPM_CRB_R_MAX];
 };
 typedef struct CRBState CRBState;
 
@@ -67,10 +68,23 @@ static int tpm_crb_isa_pre_save(void *opaque)
     return tpm_crb_pre_save(&s->state);
 }
 
+static int tpm_crb_isa_post_load(void *opaque, int version_id)
+{
+    CRBState *s = opaque;
+
+    if (version_id == 0) {
+        tpm_crb_restore_regs(&s->state, s->legacy_regs);
+    }
+    return 0;
+}
+
 static const VMStateDescription vmstate_tpm_crb_isa = {
     .name = "tpm-crb",
+    .version_id = 1,
     .pre_save = tpm_crb_isa_pre_save,
+    .post_load = tpm_crb_isa_post_load,
     .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(legacy_regs, CRBState, TPM_CRB_R_MAX),
         VMSTATE_END_OF_LIST(),
     }
 };
diff --git a/hw/tpm/tpm_crb_common.c b/hw/tpm/tpm_crb_common.c
index 4ecf064c98..5714ac7fc4 100644
--- a/hw/tpm/tpm_crb_common.c
+++ b/hw/tpm/tpm_crb_common.c
@@ -224,3 +224,10 @@ void tpm_crb_init_memory(Object *obj, TPMCRBState *s, Error **errp)
         tpm_ppi_init_memory(&s->ppi, obj);
     }
 }
+
+void tpm_crb_restore_regs(TPMCRBState *s, uint32_t *saved_regs)
+{
+    uint32_t *regs = memory_region_get_ram_ptr(&s->mmio);
+
+    memcpy(regs, saved_regs, TPM_CRB_R_MAX);
+}
-- 
2.39.2 (Apple Git-143)