Merge tag 'uefi-20250321-pull-request' of https://gitlab.com/kraxel/qemu into staging

hw/uefi-vars: bug fixes
hw/uefi-vars: support riscv and loongarch
docs: update firmware.json spec

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* tag 'uefi-20250321-pull-request' of https://gitlab.com/kraxel/qemu:
  docs/firmware: add feature flag for host uefi variable store
  hw/uefi-vars-sysbus: allow for loongarch virt
  hw/uefi-vars-sysbus: allow for riscv virt
  hw/uefi: fix error handling in uefi_vars_json_load
  hw/uefi: fix error handling in uefi_vars_json_save
  hw/uefi: flush variable store to disk in post load

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

6 files changed, 36 insertions, 7 deletions

diff --git a/docs/interop/firmware.json b/docs/interop/firmware.json
index 57f55f6c54..745d21d822 100644
--- a/docs/interop/firmware.json
+++ b/docs/interop/firmware.json
@@ -214,13 +214,23 @@
 #                  PL011 UART. @verbose-static is mutually exclusive
 #                  with @verbose-dynamic.
 #
+# @host-uefi-vars: The firmware expects the host to provide an uefi
+#                  variable store.  qemu supports that via
+#                  "uefi-vars-sysbus" (aarch64, riscv64, loongarch64)
+#                  or "uefi-vars-x64" (x86_64) devices.  The firmware
+#                  will not use flash for nvram.  When loading the
+#                  firmware into flash the 'stateless' setup should be
+#                  used.  It is recommened to load the firmware into
+#                  memory though.
+#
 # Since: 3.0
 ##
 { 'enum' : 'FirmwareFeature',
   'data' : [ 'acpi-s3', 'acpi-s4',
              'amd-sev', 'amd-sev-es', 'amd-sev-snp',
              'intel-tdx',
-             'enrolled-keys', 'requires-smm', 'secure-boot',
+             'enrolled-keys', 'requires-smm',
+             'secure-boot', 'host-uefi-vars',
              'verbose-dynamic', 'verbose-static' ] }
 
 ##
diff --git a/hw/loongarch/virt.c b/hw/loongarch/virt.c
index a5840ff968..b6f5f6a3b5 100644
--- a/hw/loongarch/virt.c
+++ b/hw/loongarch/virt.c
@@ -38,6 +38,7 @@
 #include "hw/mem/nvdimm.h"
 #include "hw/platform-bus.h"
 #include "hw/display/ramfb.h"
+#include "hw/uefi/var-service-api.h"
 #include "hw/mem/pc-dimm.h"
 #include "system/tpm.h"
 #include "system/block-backend.h"
@@ -1207,6 +1208,7 @@ static void virt_class_init(ObjectClass *oc, void *data)
     object_class_property_set_description(oc, "v-eiointc",
                             "Enable Virt Extend I/O Interrupt Controller.");
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE);
+    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_UEFI_VARS_SYSBUS);
 #ifdef CONFIG_TPM
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_TPM_TIS_SYSBUS);
 #endif
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index dae46f4733..e517002fdf 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -57,6 +57,7 @@
 #include "hw/acpi/aml-build.h"
 #include "qapi/qapi-visit-common.h"
 #include "hw/virtio/virtio-iommu.h"
+#include "hw/uefi/var-service-api.h"
 
 /* KVM AIA only supports APLIC MSI. APLIC Wired is always emulated by QEMU. */
 static bool virt_use_kvm_aia_aplic_imsic(RISCVVirtAIAType aia_type)
@@ -1935,6 +1936,7 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
     hc->plug = virt_machine_device_plug_cb;
 
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE);
+    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_UEFI_VARS_SYSBUS);
 #ifdef CONFIG_TPM
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_TPM_TIS_SYSBUS);
 #endif
diff --git a/hw/uefi/Kconfig b/hw/uefi/Kconfig
index ca6c2bc46a..046d55320e 100644
--- a/hw/uefi/Kconfig
+++ b/hw/uefi/Kconfig
@@ -1,3 +1,3 @@
 config UEFI_VARS
 	bool
-        default y if X86_64 || AARCH64
+        default y if X86_64 || AARCH64 || RISCV64 || LOONGARCH64
diff --git a/hw/uefi/var-service-core.c b/hw/uefi/var-service-core.c
index 8ed8378ab9..4836a0cb81 100644
--- a/hw/uefi/var-service-core.c
+++ b/hw/uefi/var-service-core.c
@@ -29,6 +29,7 @@ static int uefi_vars_post_load(void *opaque, int version_id)
     uefi_vars_state *uv = opaque;
 
     uefi_vars_update_storage(uv);
+    uefi_vars_json_save(uv);
     uv->buffer = g_malloc(uv->buf_size);
     return 0;
 }
diff --git a/hw/uefi/var-service-json.c b/hw/uefi/var-service-json.c
index 761082c11f..ad3462cd15 100644
--- a/hw/uefi/var-service-json.c
+++ b/hw/uefi/var-service-json.c
@@ -178,7 +178,7 @@ void uefi_vars_json_init(uefi_vars_state *uv, Error **errp)
 
 void uefi_vars_json_save(uefi_vars_state *uv)
 {
-    GString *gstr;
+    g_autoptr(GString) gstr = NULL;
     int rc;
 
     if (uv->jsonfd == -1) {
@@ -187,18 +187,25 @@ void uefi_vars_json_save(uefi_vars_state *uv)
 
     gstr = uefi_vars_to_json(uv);
 
-    lseek(uv->jsonfd, 0, SEEK_SET);
+    rc = lseek(uv->jsonfd, 0, SEEK_SET);
+    if (rc < 0) {
+        warn_report("%s: lseek error", __func__);
+        return;
+    }
+
     rc = ftruncate(uv->jsonfd, 0);
     if (rc != 0) {
         warn_report("%s: ftruncate error", __func__);
+        return;
     }
+
     rc = write(uv->jsonfd, gstr->str, gstr->len);
     if (rc != gstr->len) {
         warn_report("%s: write error", __func__);
+        return;
     }
-    fsync(uv->jsonfd);
 
-    g_string_free(gstr, true);
+    fsync(uv->jsonfd);
 }
 
 void uefi_vars_json_load(uefi_vars_state *uv, Error **errp)
@@ -207,7 +214,7 @@ void uefi_vars_json_load(uefi_vars_state *uv, Error **errp)
     QObject *qobj;
     Visitor *v;
     char *str;
-    size_t len;
+    ssize_t len;
     int rc;
 
     if (uv->jsonfd == -1) {
@@ -215,7 +222,12 @@ void uefi_vars_json_load(uefi_vars_state *uv, Error **errp)
     }
 
     len = lseek(uv->jsonfd, 0, SEEK_END);
+    if (len < 0) {
+        warn_report("%s: lseek error", __func__);
+        return;
+    }
     if (len == 0) {
+        /* empty file */
         return;
     }
 
@@ -224,6 +236,8 @@ void uefi_vars_json_load(uefi_vars_state *uv, Error **errp)
     rc = read(uv->jsonfd, str, len);
     if (rc != len) {
         warn_report("%s: read error", __func__);
+        g_free(str);
+        return;
     }
     str[len] = 0;