* Bug fixes

* Pass random seed to x86 and other FDT platforms
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Merge tag 'for-upstream2' of https://gitlab.com/bonzini/qemu into staging

* Bug fixes
* Pass random seed to x86 and other FDT platforms

# gpg: Signature made Fri 22 Jul 2022 18:26:45 BST
# gpg:                using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg:                issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* tag 'for-upstream2' of https://gitlab.com/bonzini/qemu:
  hw/i386: pass RNG seed via setup_data entry
  hw/rx: pass random seed to fdt
  hw/mips: boston: pass random seed to fdt
  hw/nios2: virt: pass random seed to fdt
  oss-fuzz: ensure base_copy is a generic-fuzzer
  oss-fuzz: remove binaries from qemu-bundle tree
  accel/kvm: Avoid Coverity warning in query_stats()
  docs: Add caveats for Windows as the build platform

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

accel/kvm/kvm-all.c

@@ -4014,7 +4014,7 @@ static void query_stats(StatsResultList **result, StatsTarget target,
                         stats_list);
         break;
     default:
-        break;
+        g_assert_not_reached();
     }
 }
 

docs/about/build-platforms.rst

@@ -94,8 +94,16 @@ not tested anymore, so it is recommended to use one of the latest versions of
 Windows instead.
 
 The project supports building QEMU with current versions of the MinGW
-toolchain, either hosted on Linux (Debian/Fedora) or via MSYS2 on Windows.
+toolchain, either hosted on Linux (Debian/Fedora) or via `MSYS2`_ on Windows.
+A more recent Windows version is always preferred as it is less likely to have
+problems with building via MSYS2. The building process of QEMU involves some
+Python scripts that call os.symlink() which needs special attention for the
+build process to successfully complete. On newer versions of Windows 10,
+unprivileged accounts can create symlinks if Developer Mode is enabled.
+When Developer Mode is not available/enabled, the SeCreateSymbolicLinkPrivilege
+privilege is required, or the process must be run as an administrator.
 
 .. _Homebrew: https://brew.sh/
 .. _MacPorts: https://www.macports.org/
+.. _MSYS2: https://www.msys2.org/
 .. _Repology: https://repology.org/

hw/i386/microvm.c

@@ -332,7 +332,7 @@ static void microvm_memory_init(MicrovmMachineState *mms)
     rom_set_fw(fw_cfg);
 
     if (machine->kernel_filename != NULL) {
-        x86_load_linux(x86ms, fw_cfg, 0, true);
+        x86_load_linux(x86ms, fw_cfg, 0, true, false);
     }
 
     if (mms->option_roms) {

hw/i386/pc.c

@@ -796,7 +796,7 @@ void xen_load_linux(PCMachineState *pcms)
     rom_set_fw(fw_cfg);
 
     x86_load_linux(x86ms, fw_cfg, pcmc->acpi_data_size,
-                   pcmc->pvh_enabled);
+                   pcmc->pvh_enabled, pcmc->legacy_no_rng_seed);
     for (i = 0; i < nb_option_roms; i++) {
         assert(!strcmp(option_rom[i].name, "linuxboot.bin") ||
                !strcmp(option_rom[i].name, "linuxboot_dma.bin") ||
@@ -992,7 +992,7 @@ void pc_memory_init(PCMachineState *pcms,
 
     if (linux_boot) {
         x86_load_linux(x86ms, fw_cfg, pcmc->acpi_data_size,
-                       pcmc->pvh_enabled);
+                       pcmc->pvh_enabled, pcmc->legacy_no_rng_seed);
     }
 
     for (i = 0; i < nb_option_roms; i++) {

hw/i386/pc_piix.c

@@ -438,9 +438,11 @@ DEFINE_I440FX_MACHINE(v7_1, "pc-i440fx-7.1", NULL,
 
 static void pc_i440fx_7_0_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_i440fx_7_1_machine_options(m);
     m->alias = NULL;
     m->is_default = false;
+    pcmc->legacy_no_rng_seed = true;
     compat_props_add(m->compat_props, hw_compat_7_0, hw_compat_7_0_len);
     compat_props_add(m->compat_props, pc_compat_7_0, pc_compat_7_0_len);
 }

hw/i386/pc_q35.c

@@ -375,8 +375,10 @@ DEFINE_Q35_MACHINE(v7_1, "pc-q35-7.1", NULL,
 
 static void pc_q35_7_0_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_7_1_machine_options(m);
     m->alias = NULL;
+    pcmc->legacy_no_rng_seed = true;
     compat_props_add(m->compat_props, hw_compat_7_0, hw_compat_7_0_len);
     compat_props_add(m->compat_props, pc_compat_7_0, pc_compat_7_0_len);
 }

hw/i386/x86.c

@@ -26,6 +26,7 @@
 #include "qemu/cutils.h"
 #include "qemu/units.h"
 #include "qemu/datadir.h"
+#include "qemu/guest-random.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qerror.h"
 #include "qapi/qapi-visit-common.h"
@@ -766,7 +767,8 @@ static bool load_elfboot(const char *kernel_filename,
 void x86_load_linux(X86MachineState *x86ms,
                     FWCfgState *fw_cfg,
                     int acpi_data_size,
-                    bool pvh_enabled)
+                    bool pvh_enabled,
+                    bool legacy_no_rng_seed)
 {
     bool linuxboot_dma_enabled = X86_MACHINE_GET_CLASS(x86ms)->fwcfg_dma_enabled;
     uint16_t protocol;
@@ -774,7 +776,7 @@ void x86_load_linux(X86MachineState *x86ms,
     int dtb_size, setup_data_offset;
     uint32_t initrd_max;
     uint8_t header[8192], *setup, *kernel;
-    hwaddr real_addr, prot_addr, cmdline_addr, initrd_addr = 0;
+    hwaddr real_addr, prot_addr, cmdline_addr, initrd_addr = 0, first_setup_data = 0;
     FILE *f;
     char *vmode;
     MachineState *machine = MACHINE(x86ms);
@@ -784,6 +786,7 @@ void x86_load_linux(X86MachineState *x86ms,
     const char *dtb_filename = machine->dtb;
     const char *kernel_cmdline = machine->kernel_cmdline;
     SevKernelLoaderContext sev_load_ctx = {};
+    enum { RNG_SEED_LENGTH = 32 };
 
     /* Align to 16 bytes as a paranoia measure */
     cmdline_size = (strlen(kernel_cmdline) + 16) & ~15;
@@ -1063,16 +1066,31 @@ void x86_load_linux(X86MachineState *x86ms,
         kernel_size = setup_data_offset + sizeof(struct setup_data) + dtb_size;
         kernel = g_realloc(kernel, kernel_size);
 
-        stq_p(header + 0x250, prot_addr + setup_data_offset);
 
         setup_data = (struct setup_data *)(kernel + setup_data_offset);
-        setup_data->next = 0;
+        setup_data->next = cpu_to_le64(first_setup_data);
+        first_setup_data = prot_addr + setup_data_offset;
         setup_data->type = cpu_to_le32(SETUP_DTB);
         setup_data->len = cpu_to_le32(dtb_size);
 
         load_image_size(dtb_filename, setup_data->data, dtb_size);
     }
 
+    if (!legacy_no_rng_seed) {
+        setup_data_offset = QEMU_ALIGN_UP(kernel_size, 16);
+        kernel_size = setup_data_offset + sizeof(struct setup_data) + RNG_SEED_LENGTH;
+        kernel = g_realloc(kernel, kernel_size);
+        setup_data = (struct setup_data *)(kernel + setup_data_offset);
+        setup_data->next = cpu_to_le64(first_setup_data);
+        first_setup_data = prot_addr + setup_data_offset;
+        setup_data->type = cpu_to_le32(SETUP_RNG_SEED);
+        setup_data->len = cpu_to_le32(RNG_SEED_LENGTH);
+        qemu_guest_getrandom_nofail(setup_data->data, RNG_SEED_LENGTH);
+    }
+
+    /* Offset 0x250 is a pointer to the first setup_data link. */
+    stq_p(header + 0x250, first_setup_data);
+
     /*
      * If we're starting an encrypted VM, it will be OVMF based, which uses the
      * efi stub for booting and doesn't require any values to be placed in the

hw/mips/boston.c

@@ -34,6 +34,7 @@
 #include "hw/qdev-properties.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
+#include "qemu/guest-random.h"
 #include "qemu/log.h"
 #include "chardev/char.h"
 #include "sysemu/device_tree.h"
@@ -363,6 +364,7 @@ static const void *boston_fdt_filter(void *opaque, const void *fdt_orig,
     size_t ram_low_sz, ram_high_sz;
     size_t fdt_sz = fdt_totalsize(fdt_orig) * 2;
     g_autofree void *fdt = g_malloc0(fdt_sz);
+    uint8_t rng_seed[32];
 
     err = fdt_open_into(fdt_orig, fdt, fdt_sz);
     if (err) {
@@ -370,6 +372,9 @@ static const void *boston_fdt_filter(void *opaque, const void *fdt_orig,
         return NULL;
     }
 
+    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
+    qemu_fdt_setprop(fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
+
     cmdline = (machine->kernel_cmdline && machine->kernel_cmdline[0])
             ? machine->kernel_cmdline : " ";
     err = qemu_fdt_setprop_string(fdt, "/chosen", "bootargs", cmdline);

hw/nios2/boot.c

@@ -34,6 +34,7 @@
 #include "qemu/option.h"
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
+#include "qemu/guest-random.h"
 #include "sysemu/device_tree.h"
 #include "sysemu/reset.h"
 #include "hw/boards.h"
@@ -83,6 +84,7 @@ static int nios2_load_dtb(struct nios2_boot_info bi, const uint32_t ramsize,
     int fdt_size;
     void *fdt = NULL;
     int r;
+    uint8_t rng_seed[32];
 
     if (dtb_filename) {
         fdt = load_device_tree(dtb_filename, &fdt_size);
@@ -91,6 +93,9 @@ static int nios2_load_dtb(struct nios2_boot_info bi, const uint32_t ramsize,
         return 0;
     }
 
+    qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
+    qemu_fdt_setprop(fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
+
     if (kernel_cmdline) {
         r = qemu_fdt_setprop_string(fdt, "/chosen", "bootargs",
                                     kernel_cmdline);

hw/rx/rx-gdbsim.c

@@ -19,6 +19,7 @@
 #include "qemu/osdep.h"
 #include "qemu/cutils.h"
 #include "qemu/error-report.h"
+#include "qemu/guest-random.h"
 #include "qapi/error.h"
 #include "hw/loader.h"
 #include "hw/rx/rx62n.h"
@@ -83,6 +84,7 @@ static void rx_gdbsim_init(MachineState *machine)
     MemoryRegion *sysmem = get_system_memory();
     const char *kernel_filename = machine->kernel_filename;
     const char *dtb_filename = machine->dtb;
+    uint8_t rng_seed[32];
 
     if (machine->ram_size < mc->default_ram_size) {
         char *sz = size_to_str(mc->default_ram_size);
@@ -140,6 +142,8 @@ static void rx_gdbsim_init(MachineState *machine)
                 error_report("Couldn't set /chosen/bootargs");
                 exit(1);
             }
+            qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed));
+            qemu_fdt_setprop(dtb, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed));
             /* DTB is located at the end of SDRAM space. */
             dtb_offset = ROUND_DOWN(machine->ram_size - dtb_size, 16);
             rom_add_blob_fixed("dtb", dtb, dtb_size,

include/hw/i386/pc.h

@@ -127,6 +127,9 @@ struct PCMachineClass {
 
     /* create kvmclock device even when KVM PV features are not exposed */
     bool kvmclock_create_always;
+
+    /* skip passing an rng seed for legacy machines */
+    bool legacy_no_rng_seed;
 };
 
 #define TYPE_PC_MACHINE "generic-pc-machine"

include/hw/i386/x86.h

@@ -123,7 +123,8 @@ void x86_bios_rom_init(MachineState *ms, const char *default_firmware,
 void x86_load_linux(X86MachineState *x86ms,
                     FWCfgState *fw_cfg,
                     int acpi_data_size,
-                    bool pvh_enabled);
+                    bool pvh_enabled,
+                    bool legacy_no_rng_seed);
 
 bool x86_machine_is_smm_enabled(const X86MachineState *x86ms);
 bool x86_machine_is_acpi_enabled(const X86MachineState *x86ms);

include/standard-headers/asm-x86/bootparam.h

@@ -10,6 +10,7 @@
 #define SETUP_EFI			4
 #define SETUP_APPLE_PROPERTIES		5
 #define SETUP_JAILHOUSE			6
+#define SETUP_RNG_SEED			9
 
 #define SETUP_INDIRECT			(1<<31)
 

scripts/oss-fuzz/build.sh

@@ -87,10 +87,12 @@ if [ "$GITLAB_CI" != "true" ]; then
     make "-j$(nproc)" qemu-fuzz-i386 V=1
 fi
 
-# Prepare a preinstalled tree
+# Place data files in the preinstall tree
 make install DESTDIR=$DEST_DIR/qemu-bundle
+rm -rf $DEST_DIR/qemu-bundle/opt/qemu-oss-fuzz/bin
+rm -rf $DEST_DIR/qemu-bundle/opt/qemu-oss-fuzz/libexec
 
-targets=$(./qemu-fuzz-i386 | awk '$1 ~ /\*/  {print $2}')
+targets=$(./qemu-fuzz-i386 | grep generic-fuzz | awk '$1 ~ /\*/  {print $2}')
 base_copy="$DEST_DIR/qemu-fuzz-i386-target-$(echo "$targets" | head -n 1)"
 
 cp "./qemu-fuzz-i386" "$base_copy"