Messages in this thread Patch in this message | | | From | "Jason A. Donenfeld" <> | Subject | [PATCH] x86: temporarily remove all attempts to provide setup_data | Date | Wed, 8 Feb 2023 15:08:35 -0300 |
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All attempts at providing setup_data have been made as an iteration on whatever was there before, stretching back to the original implementation used for DTBs that [mis]used the kernel image itself. We've now had a dozen rounds of bugs and hacks, and the result is turning into a pile of unmaintainable and increasingly brittle hacks.
Let's just rip out all the madness and start over. We can re-architect this based on having a separate standalone setup_data file, which is how it should have been done in the first place. This is a larger project with a few things to coordinate, but we can't really begin thinking about that while trying to play whack-a-mole with the current buggy implementation.
So this commit removes the setup_data setting from x86_load_linux(), while leaving intact the infrastructure we'll need in the future to try again.
Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Dov Murik <dovmurik@linux.ibm.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Daniel P. Berrangé <berrange@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Philippe Mathieu-Daudé <philmd@linaro.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- hw/i386/microvm.c | 15 ++---- hw/i386/x86.c | 120 +++++----------------------------------------- 2 files changed, 17 insertions(+), 118 deletions(-)
diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c index 29f30dd6d3..170a331e3f 100644 --- a/hw/i386/microvm.c +++ b/hw/i386/microvm.c @@ -378,8 +378,7 @@ static void microvm_fix_kernel_cmdline(MachineState *machine) MicrovmMachineState *mms = MICROVM_MACHINE(machine); BusState *bus; BusChild *kid; - char *cmdline, *existing_cmdline; - size_t len; + char *cmdline; /* * Find MMIO transports with attached devices, and add them to the kernel @@ -388,8 +387,7 @@ static void microvm_fix_kernel_cmdline(MachineState *machine) * Yes, this is a hack, but one that heavily improves the UX without * introducing any significant issues. */ - existing_cmdline = fw_cfg_read_bytes_ptr(x86ms->fw_cfg, FW_CFG_CMDLINE_DATA); - cmdline = g_strdup(existing_cmdline); + cmdline = g_strdup(machine->kernel_cmdline); bus = sysbus_get_default(); QTAILQ_FOREACH(kid, &bus->children, sibling) { DeviceState *dev = kid->child; @@ -413,12 +411,9 @@ static void microvm_fix_kernel_cmdline(MachineState *machine) } } - len = strlen(cmdline); - if (len > VIRTIO_CMDLINE_TOTAL_MAX_LEN + strlen(existing_cmdline)) { - fprintf(stderr, "qemu: virtio mmio cmdline too large, skipping\n"); - } else { - memcpy(existing_cmdline, cmdline, len + 1); - } + fw_cfg_modify_i32(x86ms->fw_cfg, FW_CFG_CMDLINE_SIZE, strlen(cmdline) + 1); + fw_cfg_modify_string(x86ms->fw_cfg, FW_CFG_CMDLINE_DATA, cmdline); + g_free(cmdline); } diff --git a/hw/i386/x86.c b/hw/i386/x86.c index eaff4227bd..6cfdca9acd 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -50,7 +50,6 @@ #include "hw/intc/i8259.h" #include "hw/rtc/mc146818rtc.h" #include "target/i386/sev.h" -#include "hw/i386/microvm.h" #include "hw/acpi/cpu_hotplug.h" #include "hw/irq.h" @@ -770,30 +769,6 @@ static bool load_elfboot(const char *kernel_filename, return true; } -typedef struct SetupDataFixup { - void *pos; - hwaddr orig_val, new_val; - uint32_t addr; -} SetupDataFixup; - -static void fixup_setup_data(void *opaque) -{ - SetupDataFixup *fixup = opaque; - stq_p(fixup->pos, fixup->new_val); -} - -static void reset_setup_data(void *opaque) -{ - SetupDataFixup *fixup = opaque; - stq_p(fixup->pos, fixup->orig_val); -} - -static void reset_rng_seed(void *opaque) -{ - SetupData *setup_data = opaque; - qemu_guest_getrandom_nofail(setup_data->data, le32_to_cpu(setup_data->len)); -} - void x86_load_linux(X86MachineState *x86ms, FWCfgState *fw_cfg, int acpi_data_size, @@ -803,29 +778,20 @@ void x86_load_linux(X86MachineState *x86ms, bool linuxboot_dma_enabled = X86_MACHINE_GET_CLASS(x86ms)->fwcfg_dma_enabled; uint16_t protocol; int setup_size, kernel_size, cmdline_size; - 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); - SetupData *setup_data; const char *kernel_filename = machine->kernel_filename; const char *initrd_filename = machine->initrd_filename; - const char *dtb_filename = machine->dtb; - char *kernel_cmdline; + const char *kernel_cmdline = machine->kernel_cmdline; SevKernelLoaderContext sev_load_ctx = {}; enum { RNG_SEED_LENGTH = 32 }; - /* - * Add the NUL terminator, some padding for the microvm cmdline fiddling - * hack, and then align to 16 bytes as a paranoia measure - */ - cmdline_size = (strlen(machine->kernel_cmdline) + 1 + - VIRTIO_CMDLINE_TOTAL_MAX_LEN + 16) & ~15; - /* Make a copy, since we might append arbitrary bytes to it later. */ - kernel_cmdline = g_strndup(machine->kernel_cmdline, cmdline_size); + /* Align to 16 bytes as a paranoia measure */ + cmdline_size = (strlen(kernel_cmdline) + 16) & ~15; /* load the kernel header */ f = fopen(kernel_filename, "rb"); @@ -966,6 +932,12 @@ void x86_load_linux(X86MachineState *x86ms, initrd_max = x86ms->below_4g_mem_size - acpi_data_size - 1; } + fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_ADDR, cmdline_addr); + fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE, strlen(kernel_cmdline) + 1); + fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA, kernel_cmdline); + sev_load_ctx.cmdline_data = (char *)kernel_cmdline; + sev_load_ctx.cmdline_size = strlen(kernel_cmdline) + 1; + if (protocol >= 0x202) { stl_p(header + 0x228, cmdline_addr); } else { @@ -1078,81 +1050,13 @@ void x86_load_linux(X86MachineState *x86ms, } fclose(f); - /* append dtb to kernel */ - if (dtb_filename) { - if (protocol < 0x209) { - fprintf(stderr, "qemu: Linux kernel too old to load a dtb\n"); - exit(1); - } - - dtb_size = get_image_size(dtb_filename); - if (dtb_size <= 0) { - fprintf(stderr, "qemu: error reading dtb %s: %s\n", - dtb_filename, strerror(errno)); - exit(1); - } - - setup_data_offset = cmdline_size; - cmdline_size += sizeof(SetupData) + dtb_size; - kernel_cmdline = g_realloc(kernel_cmdline, cmdline_size); - setup_data = (void *)kernel_cmdline + setup_data_offset; - setup_data->next = cpu_to_le64(first_setup_data); - first_setup_data = cmdline_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 && protocol >= 0x209) { - setup_data_offset = cmdline_size; - cmdline_size += sizeof(SetupData) + RNG_SEED_LENGTH; - kernel_cmdline = g_realloc(kernel_cmdline, cmdline_size); - setup_data = (void *)kernel_cmdline + setup_data_offset; - setup_data->next = cpu_to_le64(first_setup_data); - first_setup_data = cmdline_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); - qemu_register_reset_nosnapshotload(reset_rng_seed, setup_data); - fw_cfg_add_bytes_callback(fw_cfg, FW_CFG_KERNEL_DATA, reset_rng_seed, NULL, - setup_data, kernel, kernel_size, true); - } else { - fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA, kernel, kernel_size); - } - - fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_ADDR, cmdline_addr); - fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE, cmdline_size); - fw_cfg_add_bytes(fw_cfg, FW_CFG_CMDLINE_DATA, kernel_cmdline, cmdline_size); - sev_load_ctx.cmdline_data = (char *)kernel_cmdline; - sev_load_ctx.cmdline_size = cmdline_size; - + fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA, kernel, kernel_size); fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, prot_addr); fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, kernel_size); sev_load_ctx.kernel_data = (char *)kernel; sev_load_ctx.kernel_size = kernel_size; - /* - * 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 - * kernel header. We therefore don't update the header so the hash of the - * kernel on the other side of the fw_cfg interface matches the hash of the - * file the user passed in. - */ - if (!sev_enabled() && first_setup_data) { - SetupDataFixup *fixup = g_malloc(sizeof(*fixup)); - - memcpy(setup, header, MIN(sizeof(header), setup_size)); - /* Offset 0x250 is a pointer to the first setup_data link. */ - fixup->pos = setup + 0x250; - fixup->orig_val = ldq_p(fixup->pos); - fixup->new_val = first_setup_data; - fixup->addr = cpu_to_le32(real_addr); - fw_cfg_add_bytes_callback(fw_cfg, FW_CFG_SETUP_ADDR, fixup_setup_data, NULL, - fixup, &fixup->addr, sizeof(fixup->addr), true); - qemu_register_reset(reset_setup_data, fixup); - } else { - fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_ADDR, real_addr); - } + fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_ADDR, real_addr); fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_SIZE, setup_size); fw_cfg_add_bytes(fw_cfg, FW_CFG_SETUP_DATA, setup, setup_size); sev_load_ctx.setup_data = (char *)setup; -- 2.39.1
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