Date:   Wed, 8 Feb 2023 16:12:56 -0500
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     qemu-devel@nongnu.org, "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org,
        Dov Murik <dovmurik@linux.ibm.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Daniel P =?utf-8?B?LiBCZXJyYW5nw6k=?= <berrange@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Richard Henderson <richard.henderson@linaro.org>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= <philmd@linaro.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Eric Biggers <ebiggers@kernel.org>,
        Sergio Lopez <slp@redhat.com>,
        Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,
        Eduardo Habkost <eduardo@habkost.net>
Subject: [PATCH RFC 7/7] Revert "hw/i386: pass RNG seed via setup_data entry"
Message-ID: <20230208211212.41951-8-mst@redhat.com>
References: <20230208211212.41951-1-mst@redhat.com>
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In-Reply-To: <20230208211212.41951-1-mst@redhat.com>
Precedence: bulk

This reverts commit 67f7e426e53833a5db75b0d813e8d537b8a75bd2.

Fixes: 67f7e426e5 ("hw/i386: pass RNG seed via setup_data entry")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/hw/i386/pc.h  |  3 ---
 include/hw/i386/x86.h |  3 +--
 hw/i386/microvm.c     |  2 +-
 hw/i386/pc.c          |  4 ++--
 hw/i386/pc_piix.c     |  2 --
 hw/i386/pc_q35.c      |  2 --
 hw/i386/x86.c         | 26 ++++----------------------
 7 files changed, 8 insertions(+), 34 deletions(-)

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 66e3d059ef..44b08554fa 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -127,9 +127,6 @@ 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"
diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h
index 62fa5774f8..df82c5fd42 100644
--- a/include/hw/i386/x86.h
+++ b/include/hw/i386/x86.h
@@ -126,8 +126,7 @@ 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 legacy_no_rng_seed);
+                    bool pvh_enabled);
 
 bool x86_machine_is_smm_enabled(const X86MachineState *x86ms);
 bool x86_machine_is_acpi_enabled(const X86MachineState *x86ms);
diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index 170a331e3f..b231ceda9a 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -330,7 +330,7 @@ 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, false);
+        x86_load_linux(x86ms, fw_cfg, 0, true);
     }
 
     if (mms->option_roms) {
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 6e592bd969..2c5f675ba4 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -804,7 +804,7 @@ 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->legacy_no_rng_seed);
+                   pcmc->pvh_enabled);
     for (i = 0; i < nb_option_roms; i++) {
         assert(!strcmp(option_rom[i].name, "linuxboot.bin") ||
                !strcmp(option_rom[i].name, "linuxboot_dma.bin") ||
@@ -1124,7 +1124,7 @@ void pc_memory_init(PCMachineState *pcms,
 
     if (linux_boot) {
         x86_load_linux(x86ms, fw_cfg, pcmc->acpi_data_size,
-                       pcmc->pvh_enabled, pcmc->legacy_no_rng_seed);
+                       pcmc->pvh_enabled);
     }
 
     for (i = 0; i < nb_option_roms; i++) {
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index df64dd8dcc..839bd65df5 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -476,9 +476,7 @@ DEFINE_I440FX_MACHINE(v7_2, "pc-i440fx-7.2", NULL,
 
 static void pc_i440fx_7_1_machine_options(MachineClass *m)
 {
-    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_i440fx_7_2_machine_options(m);
-    pcmc->legacy_no_rng_seed = true;
     compat_props_add(m->compat_props, hw_compat_7_1, hw_compat_7_1_len);
     compat_props_add(m->compat_props, pc_compat_7_1, pc_compat_7_1_len);
 }
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 66cd718b70..e6e3966262 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -395,9 +395,7 @@ DEFINE_Q35_MACHINE(v7_2, "pc-q35-7.2", NULL,
 
 static void pc_q35_7_1_machine_options(MachineClass *m)
 {
-    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_7_2_machine_options(m);
-    pcmc->legacy_no_rng_seed = true;
     compat_props_add(m->compat_props, hw_compat_7_1, hw_compat_7_1_len);
     compat_props_add(m->compat_props, pc_compat_7_1, pc_compat_7_1_len);
 }
diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index 4831193c86..80be3032cc 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -26,7 +26,6 @@
 #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"
@@ -771,8 +770,7 @@ 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 legacy_no_rng_seed)
+                    bool pvh_enabled)
 {
     bool linuxboot_dma_enabled = X86_MACHINE_GET_CLASS(x86ms)->fwcfg_dma_enabled;
     uint16_t protocol;
@@ -780,7 +778,7 @@ 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, first_setup_data = 0;
+    hwaddr real_addr, prot_addr, cmdline_addr, initrd_addr = 0;
     FILE *f;
     char *vmode;
     MachineState *machine = MACHINE(x86ms);
@@ -790,7 +788,6 @@ 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;
@@ -1070,31 +1067,16 @@ 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 = cpu_to_le64(first_setup_data);
-        first_setup_data = prot_addr + setup_data_offset;
+        setup_data->next = 0;
         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
-- 
MST