On 9/4/26 5:35 AM, Mathieu Poirier wrote:
From: Jean-Philippe Brucker <[email protected]>
Add a Rom notifier to keep track of binary blobs loaded in Realm memory.
That way we can deterministically calculate the Realm Initial Measurement (RIM).
Signed-off-by: Jean-Philippe Brucker <[email protected]>
Signed-off-by: Lorenzo Pieralisi <[email protected]>
Signed-off-by: Mathieu Poirier <[email protected]>
---
target/arm/kvm-rme.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/target/arm/kvm-rme.c b/target/arm/kvm-rme.c
index f7c2cc786e2c..9985f5daba89 100644
--- a/target/arm/kvm-rme.c
+++ b/target/arm/kvm-rme.c
@@ -10,6 +10,7 @@
#include "hw/core/boards.h"
#include "hw/core/cpu.h"
+#include "hw/core/loader.h"
#include "kvm_arm.h"
#include "migration/blocker.h"
#include "qapi/error.h"
@@ -22,8 +23,18 @@
#define TYPE_RME_GUEST "rme-guest"
OBJECT_DECLARE_SIMPLE_TYPE(RmeGuest, RME_GUEST)
+#define RME_PAGE_SIZE qemu_real_host_page_size()
+
+typedef struct {
+ hwaddr base;
+ hwaddr size;
+ uint8_t *data;
+} RmeRamRegion;
+
This is the equivalent to 'RomLoaderNotifyData' defined in PATCH[09/24]. We may
use 'RomLoaderNotifyData' if it can be renamed to reflect its purpose, no need
to define an identical structure.
struct RmeGuest {
ConfidentialGuestSupport parent_obj;
+ Notifier rom_load_notifier;
+ GSList *ram_regions;
};
OBJECT_DEFINE_SIMPLE_TYPE_WITH_INTERFACES(RmeGuest, rme_guest, RME_GUEST,
@@ -41,6 +52,44 @@ static void rme_vm_state_change(void *opaque, bool running,
RunState state)
kvm_mark_guest_state_protected();
}
+static gint rme_compare_ram_regions(gconstpointer a, gconstpointer b)
+{
+ const RmeRamRegion *ra = a;
+ const RmeRamRegion *rb = b;
+
+ g_assert(ra->base != rb->base);
+ return ra->base < rb->base ? -1 : 1;
+}
+
+static void rme_rom_load_notify(Notifier *notifier, void *data)
+{
+ RmeRamRegion *region;
+ RomLoaderNotifyData *rom = data;
+
+ if (rom->addr == -1) {
+ /*
+ * These blobs (ACPI tables) are not loaded into guest RAM at reset.
+ * Instead the firmware will load them via fw_cfg and measure them
+ * itself.
+ */
+ return;
+ }
+
+ region = g_new0(RmeRamRegion, 1);
+ region->base = rom->addr;
+ region->size = rom->len;
+ region->data = rom->data;
+
+ /*
+ * The Realm Initial Measurement (RIM) depends on the order in which we
+ * initialize and populate the RAM regions. To help a verifier
+ * independently calculate the RIM, sort regions by GPA.
+ */
+ rme_guest->ram_regions = g_slist_insert_sorted(rme_guest->ram_regions,
+ region,
+ rme_compare_ram_regions);
+}
+
static int kvm_arm_rme_init(ConfidentialGuestSupport *cgs, Error **errp)
{
KVMState *s = KVM_STATE(current_accel());
@@ -58,6 +107,9 @@ static int kvm_arm_rme_init(ConfidentialGuestSupport *cgs,
Error **errp)
error_setg(&rme_mig_blocker, "RME: migration is not implemented");
migrate_add_blocker(&rme_mig_blocker, &error_fatal);
+ rme_guest->rom_load_notifier.notify = rme_rom_load_notify;
+ rom_add_load_notifier(&rme_guest->rom_load_notifier);
+
/*
* The realm activation is done last, when the VM starts, after all images
* have been loaded and all vcpus finalized.
Thanks,
Gavin
