[PATCH v3 48/70] i386/tdx: register TDVF as private memory

[Xiaoyao Li <xiaoyao.li@xxxxxxxxx>]

From: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>

Allocate private guest memfd memory for BIOS if it's TD VM.

Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
Co-developed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
 hw/i386/x86.c         | 10 +++++++++-
 target/i386/kvm/tdx.c | 18 ++++++++++++++++++
 target/i386/kvm/tdx.h |  2 ++
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index 2f299355a5e3..0f69b55c5219 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -1146,8 +1146,16 @@ void x86_bios_rom_init(MachineState *ms, const char *default_firmware,
         (bios_size % 65536) != 0) {
         goto bios_error;
     }
+
     bios = g_malloc(sizeof(*bios));
-    memory_region_init_ram(bios, NULL, "pc.bios", bios_size, &error_fatal);
+    if (is_tdx_vm()) {
+        memory_region_init_ram_guest_memfd(bios, NULL, "pc.bios", bios_size,
+                                           &error_fatal);
+        tdx_set_tdvf_region(bios);
+    } else {
+        memory_region_init_ram(bios, NULL, "pc.bios", bios_size, &error_fatal);
+    }
+
     if (sev_enabled() || is_tdx_vm()) {
         /*
          * The concept of a "reset" simply doesn't exist for
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 6bb3249fa610..4b8c13890b11 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -21,6 +21,7 @@
 #include "sysemu/kvm.h"
 #include "sysemu/sysemu.h"
 #include "exec/address-spaces.h"
+#include "exec/ramblock.h"
 
 #include "hw/i386/e820_memory_layout.h"
 #include "hw/i386/x86.h"
@@ -461,6 +462,12 @@ static void update_tdx_cpuid_lookup_by_tdx_caps(void)
             (tdx_caps->xfam_fixed1 & CPUID_XSTATE_XSS_MASK) >> 32;
 }
 
+void tdx_set_tdvf_region(MemoryRegion *tdvf_region)
+{
+    assert(!tdx_guest->tdvf_region);
+    tdx_guest->tdvf_region = tdvf_region;
+}
+
 static TdxFirmwareEntry *tdx_get_hob_entry(TdxGuest *tdx)
 {
     TdxFirmwareEntry *entry;
@@ -582,6 +589,7 @@ static void tdx_finalize_vm(Notifier *notifier, void *unused)
 {
     TdxFirmware *tdvf = &tdx_guest->tdvf;
     TdxFirmwareEntry *entry;
+    RAMBlock *ram_block;
     int r;
 
     tdx_init_ram_entries();
@@ -616,6 +624,12 @@ static void tdx_finalize_vm(Notifier *notifier, void *unused)
             .nr_pages = entry->size / 4096,
         };
 
+        r = kvm_set_memory_attributes_private(entry->address, entry->size);
+        if (r < 0) {
+             error_report("Reserve initial private memory failed %s", strerror(-r));
+             exit(1);
+        }
+
         __u32 flags = entry->attributes & TDVF_SECTION_ATTRIBUTES_MR_EXTEND ?
                       KVM_TDX_MEASURE_MEMORY_REGION : 0;
 
@@ -631,6 +645,10 @@ static void tdx_finalize_vm(Notifier *notifier, void *unused)
             entry->mem_ptr = NULL;
         }
     }
+
+    /* Tdvf image was copied into private region above. It becomes unnecessary. */
+    ram_block = tdx_guest->tdvf_region->ram_block;
+    ram_block_discard_range(ram_block, 0, ram_block->max_length);
 }
 
 static Notifier tdx_machine_done_notify = {
diff --git a/target/i386/kvm/tdx.h b/target/i386/kvm/tdx.h
index 3a35a2bc0900..5fb20a5f06bb 100644
--- a/target/i386/kvm/tdx.h
+++ b/target/i386/kvm/tdx.h
@@ -38,6 +38,7 @@ typedef struct TdxGuest {
     char *mrownerconfig;    /* base64 encoded sha348 digest */
 
     TdxFirmware tdvf;
+    MemoryRegion *tdvf_region;
 
     uint32_t nr_ram_entries;
     TdxRamEntry *ram_entries;
@@ -53,6 +54,7 @@ int tdx_kvm_init(MachineState *ms, Error **errp);
 void tdx_get_supported_cpuid(uint32_t function, uint32_t index, int reg,
                              uint32_t *ret);
 int tdx_pre_create_vcpu(CPUState *cpu, Error **errp);
+void tdx_set_tdvf_region(MemoryRegion *tdvf_region);
 int tdx_parse_tdvf(void *flash_ptr, int size);
 
 #endif /* QEMU_I386_TDX_H */
-- 
2.34.1