git: afee781523e4 - main - loader.efi: Recognize new memdisk=<url> and memcd=<url> options
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Date: Fri, 26 Jun 2026 14:59:23 UTC
The branch main has been updated by imp:
URL: https://cgit.FreeBSD.org/src/commit/?id=afee781523e45198c7be0a19281bcae2c4ab66db
commit afee781523e45198c7be0a19281bcae2c4ab66db
Author: Warner Losh <imp@FreeBSD.org>
AuthorDate: 2026-06-26 14:47:36 +0000
Commit: Warner Losh <imp@FreeBSD.org>
CommitDate: 2026-06-26 14:54:37 +0000
loader.efi: Recognize new memdisk=<url> and memcd=<url> options
Support ipxe downloading of a memory disk (either presented to the OS as
a harddisk or a cd). This requires an ipxe server since it uses the ipxe
download protocol to grab the disk. If there is a disk, we add it to the
environment as a disk, and then the rest of the bootloader just sees it
and boots from it.
I've cribbed code from https://github.com/russor/memdisk_uefi and
adapted it to work in the context of the FreeBSD bootloader.
The ipxe_download.h file was created from the documentation of the
interface.
So a .ipxe file with the line
chain http://10.2.0.1/loader.efi memdisk=${cwduri}FreeBSD-15.1-RELEASE-amd64-bootonly.iso
would use the FreeBSD boot loader to boot the FreeBSD 15.1 release.
md(9) has a bug at the moment that prevents it from probing the
partitions on it.
Also, we'll automatically decompress gzip, bzip2 and zstd files
automatically.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D57677
---
stand/efi/include/ipxe_download.h | 33 +++
stand/efi/libefi/efipart.c | 8 +-
stand/efi/loader/Makefile | 4 +
stand/efi/loader/decompress.c | 421 ++++++++++++++++++++++++++++++++++++++
stand/efi/loader/decompress.h | 19 ++
stand/efi/loader/loader_efi.h | 2 +
stand/efi/loader/main.c | 13 ++
stand/efi/loader/memdisk.c | 203 ++++++++++++++++++
8 files changed, 700 insertions(+), 3 deletions(-)
diff --git a/stand/efi/include/ipxe_download.h b/stand/efi/include/ipxe_download.h
new file mode 100644
index 000000000000..dcf616da7745
--- /dev/null
+++ b/stand/efi/include/ipxe_download.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2026 Netfilix, Inc. Written by Warner Losh
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+/*
+ * IPXE protocol to download files
+ *
+ * Written from https://dox.ipxe.org/efi__download_8h.html using the names
+ * contained there for compatibility. See that for the full docs. Provides the
+ * same interface as <ipxe/efi/efi_download.h> from the ipxe distribution.
+ */
+#pragma once
+
+typedef struct _IPXE_DOWNLOAD_PROTOCOL IPXE_DOWNLOAD_PROTOCOL;
+typedef void *IPXE_DOWNLOAD_FILE;
+typedef EFI_STATUS(EFIAPI *IPXE_DOWNLOAD_DATA_CALLBACK)(IN VOID *, IN VOID *, IN UINTN, IN UINTN);
+typedef void(EFIAPI *IPXE_DOWNLOAD_FINISH_CALLBACK)(IN VOID *, IN EFI_STATUS);
+typedef EFI_STATUS(EFIAPI *IPXE_DOWNLOAD_START)(IN IPXE_DOWNLOAD_PROTOCOL *,
+ IN CHAR8 *, IN IPXE_DOWNLOAD_DATA_CALLBACK, IN IPXE_DOWNLOAD_FINISH_CALLBACK,
+ IN VOID *, OUT IPXE_DOWNLOAD_FILE *);
+typedef EFI_STATUS(EFIAPI *IPXE_DOWNLOAD_ABORT)(IN IPXE_DOWNLOAD_PROTOCOL *,
+ IN IPXE_DOWNLOAD_FILE, IN EFI_STATUS);
+typedef EFI_STATUS(EFIAPI *IPXE_DOWNLOAD_POLL) (IN IPXE_DOWNLOAD_PROTOCOL *);
+
+struct _IPXE_DOWNLOAD_PROTOCOL {
+ IPXE_DOWNLOAD_START Start;
+ IPXE_DOWNLOAD_ABORT Abort;
+ IPXE_DOWNLOAD_POLL Poll;
+};
+#define IPXE_DOWNLOAD_PROTOCOL_GUID \
+ { 0x3eaeaebd, 0xdecf, 0x493b, { 0x9b, 0xd1, 0xcd, 0xb2, 0xde, 0xca, 0xe7, 0x19 } }
diff --git a/stand/efi/libefi/efipart.c b/stand/efi/libefi/efipart.c
index e02993064d26..b4842e1b52aa 100644
--- a/stand/efi/libefi/efipart.c
+++ b/stand/efi/libefi/efipart.c
@@ -1255,11 +1255,11 @@ error:
* Predicate: is this a VirtualDisk as far as UEFI is concerned?
*/
static bool
-testmd(pdinfo_t *hd, pdinfo_t *data __unused)
+testmd(pdinfo_t *md)
{
EFI_DEVICE_PATH *node;
- node = efi_devpath_last_node(hd->pd_devpath);
+ node = efi_devpath_last_node(md->pd_devpath);
if (node == NULL)
return (false);
if (DevicePathType(node) == MEDIA_DEVICE_PATH &&
@@ -1281,7 +1281,9 @@ efiblk_memdisk_preload(void)
char key[32], value[32];
int i;
- while ((md = efipart_get_pd(&pdinfo, testmd, NULL)) != NULL) {
+ STAILQ_FOREACH(md, &pdinfo, pd_link) {
+ if (!testmd(md))
+ continue;
ram = (MEDIA_RAM_DISK_DEVICE_PATH *)efi_devpath_last_node(md->pd_devpath);
i = ram->Instance;
start = ((uint64_t)ram->StartingAddr[1] << 32) | ram->StartingAddr[0];
diff --git a/stand/efi/loader/Makefile b/stand/efi/loader/Makefile
index 44d7347ee7dd..164b16ff2a59 100644
--- a/stand/efi/loader/Makefile
+++ b/stand/efi/loader/Makefile
@@ -22,9 +22,11 @@ SRCS= autoload.c \
bootinfo.c \
conf.c \
copy.c \
+ decompress.c \
efi_main.c \
framebuffer.c \
main.c \
+ memdisk.c \
self_reloc.c \
vers.c \
gfx_fb.c \
@@ -50,6 +52,7 @@ CFLAGS.framebuffer.c += -I$(SRCTOP)/sys/teken
CFLAGS.framebuffer.c += -I${SRCTOP}/contrib/pnglite
CFLAGS.main.c += -I$(SRCTOP)/sys/teken
CFLAGS.main.c += -I${SRCTOP}/contrib/pnglite
+CFLAGS.memdisk.c += -I${.OBJDIR}
CFLAGS.gfx_fb.c += -I$(SRCTOP)/sys/teken
CFLAGS.gfx_fb.c += -I${SRCTOP}/sys/cddl/contrib/opensolaris/common/lz4
CFLAGS.gfx_fb.c += -I${SRCTOP}/contrib/pnglite
@@ -61,6 +64,7 @@ CFLAGS.gfx_fb.c += ${ZLIB_CFLAGS}
# of a short. There's no good cast to use here so just ignore the
# warnings for now.
CWARNFLAGS.main.c+= -Wno-format
+CWARNFLAGS.memdisk.c+= -Wno-format
.PATH: ${.CURDIR}/../loader
.PATH: ${.CURDIR}/../loader/arch/${__arch}
diff --git a/stand/efi/loader/decompress.c b/stand/efi/loader/decompress.c
new file mode 100644
index 000000000000..1f44d1000f11
--- /dev/null
+++ b/stand/efi/loader/decompress.c
@@ -0,0 +1,421 @@
+/*
+ * Copyright (c) 2026 Netflix, Inc. Written by Warner Losh
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "stand.h"
+#include "loader_efi.h"
+#include <efilib.h>
+#include "decompress.h"
+
+#include <zlib.h>
+#include <bzlib.h>
+#ifdef LOADER_ZFS_SUPPORT /* ZSTD only available with ZFS */
+#include <zstd.h>
+#endif
+#include <sys/_param.h>
+
+#define ULL(x) ((unsigned long long)(x))
+
+static EFI_MEMORY_TYPE mem_type = EfiReservedMemoryType;
+
+struct decomp_state
+{
+ enum compression type;
+ size_t size; /* Best guess at final size */
+ size_t alloc_size; /* Current size of `buf` */
+ size_t pages; /* Alloc_size in pages */
+ uint8_t *buf_cur; /* Current output buffer */
+ uint8_t *buf_end; /* Current end of allocated buffer */
+ EFI_PHYSICAL_ADDRESS buf; /* Decompression buffer */
+ union {
+ z_stream zstrm;
+ bz_stream bzstrm;
+#ifdef LOADER_ZFS_SUPPORT
+ ZSTD_DStream *zstdstrm;
+#endif
+ };
+ EFI_STATUS (*init)(decomp_state *dctx, uint8_t *first_buf, size_t buflen,
+ size_t size_hint);
+ enum step_return (*step)(decomp_state *dctx, uint8_t *buf, size_t len, size_t offset);
+ void (*fini)(decomp_state *dctx, bool flush);
+};
+
+static enum compression
+what_compressed(uint8_t *buf, size_t len)
+{
+ /*
+ * Failsafe
+ */
+ if (len < 32)
+ return (none);
+ if (memcmp(buf, "\x1f\x8b", 2) == 0) {
+ printf("GZIP\n");
+ return (zlib);
+ }
+ if (memcmp(buf, "BZh", 3) == 0) {
+ printf("BZIP2\n");
+ return (bzip2);
+ }
+ if (memcmp(buf, "\x28\xb5\x2f\xfd", 4) == 0) {
+ printf("zstd\n");
+ return (zstd);
+ }
+ if (memcmp(buf, "\xfd""7zXZ\x00", 6) == 0) {
+ printf("xz -- unsupproted\n");
+ } else {
+ printf("Not compressed\n");
+ }
+ return (none);
+}
+
+static EFI_STATUS
+alloc_buffer(decomp_state *dctx, size_t size)
+{
+ dctx->alloc_size = roundup2(size, EFI_PAGE_SIZE);
+ dctx->pages = dctx->alloc_size / EFI_PAGE_SIZE;
+ EFI_STATUS status = BS->AllocatePages(AllocateAnyPages, mem_type, dctx->pages, &dctx->buf);
+ if (EFI_ERROR(status)) {
+ printf("Failed to allocate memory for %llu bytes\n", ULL(dctx->alloc_size));
+ return (status);
+ }
+ BS->SetMem((void *)dctx->buf, dctx->alloc_size, 0);
+ dctx->buf_cur = (uint8_t *)dctx->buf;
+ dctx->buf_end = (uint8_t *)dctx->buf + dctx->alloc_size;
+ return (EFI_SUCCESS);
+}
+
+static EFI_STATUS
+grow_buffer(decomp_state *dctx)
+{
+ /*
+ * a 1.5 exp growth trades a few more copies for a little less waste.
+ */
+ size_t newsz = roundup2(dctx->alloc_size * 3 / 2, EFI_PAGE_SIZE);
+ size_t newpages = newsz / EFI_PAGE_SIZE;
+ EFI_PHYSICAL_ADDRESS newbuf;
+ EFI_STATUS status = BS->AllocatePages(AllocateAnyPages, mem_type, newpages, &newbuf);
+ if (EFI_ERROR(status)) {
+ printf("Failed to allocate memory for %llu bytes\n", ULL(newsz));
+ return (status);
+ }
+ memcpy((void *)newbuf, (void *)dctx->buf, dctx->alloc_size);
+ BS->FreePages(dctx->buf, dctx->pages);
+ dctx->buf = newbuf;
+ dctx->pages = newpages;
+ dctx->buf_cur = (uint8_t *)dctx->buf + dctx->alloc_size;
+ dctx->buf_end = (uint8_t *)dctx->buf + newsz;
+ BS->SetMem(dctx->buf_cur, newsz - dctx->alloc_size, 0);
+ dctx->alloc_size = newsz;
+ return (EFI_SUCCESS);
+}
+
+static void
+free_buffer(decomp_state *dctx)
+{
+ if (dctx->buf)
+ BS->FreePages(dctx->buf, dctx->pages);
+ dctx->buf = 0;
+}
+
+/*
+ * zlib supprot
+ */
+static EFI_STATUS
+zlib_init(decomp_state *dctx, uint8_t *first_buf, size_t buflen, size_t size_hint)
+{
+ z_stream *strm = &dctx->zstrm;
+
+ /*
+ * Assume 4x compression, but start at 64MB
+ */
+ dctx->size = max(size_hint * 4, M(64));
+ EFI_STATUS status = alloc_buffer(dctx, dctx->size);
+ if (EFI_ERROR(status))
+ return (status);
+ memset(strm, 0, sizeof(*strm));
+ strm->next_in = first_buf;
+ strm->avail_in = buflen;
+ return (inflateInit2(strm, 15 + 16) == Z_OK ? EFI_SUCCESS : EFI_VOLUME_CORRUPTED);
+}
+
+static enum step_return
+zlib_step(decomp_state *dctx, uint8_t *buf, size_t len, size_t offset)
+{
+ z_stream *strm = &dctx->zstrm;
+ size_t outlen = dctx->buf_end - dctx->buf_cur;
+
+ strm->next_in = buf;
+ strm->avail_in = len;
+ strm->next_out = dctx->buf_cur;
+ strm->avail_out = outlen;
+
+ int ret = inflate(strm, Z_NO_FLUSH);
+ dctx->buf_cur += outlen - strm->avail_out;
+
+ if (ret == Z_STREAM_END)
+ return (done);
+ if (ret != Z_OK)
+ return (err);
+ if (dctx->buf_cur < dctx->buf_end) /* Have output space */
+ return (ok);
+
+ /*
+ * We're out of space, grow the buffer and try again if there's buffer
+ * space. We try again recursively since we know that will usually go
+ * only 1 deep.
+ */
+ if (EFI_ERROR(grow_buffer(dctx)))
+ return (err);
+ if (strm->avail_in == 0)
+ return (ok);
+ size_t consumed = len - strm->avail_in;
+ return (zlib_step(dctx, buf + consumed, strm->avail_in, offset + consumed));
+}
+
+static void
+zlib_fini(decomp_state *dctx, bool flush)
+{
+ inflateEnd(&dctx->zstrm);
+ if (!flush)
+ return;
+ free_buffer(dctx);
+}
+
+/*
+ * Bzip2 supprot
+ */
+static EFI_STATUS
+bzip2_init(decomp_state *dctx, uint8_t *first_buf, size_t buflen, size_t size_hint)
+{
+ bz_stream *strm = &dctx->bzstrm;
+
+ /*
+ * Assume 4x compression, but start at 64MB
+ */
+ dctx->size = max(size_hint * 4, M(64));
+ EFI_STATUS status = alloc_buffer(dctx, dctx->size);
+ if (EFI_ERROR(status))
+ return (status);
+ memset(strm, 0, sizeof(*strm));
+ strm->next_in = first_buf;
+ strm->avail_in = buflen;
+ return (BZ2_bzDecompressInit(strm, 0, 0) == BZ_OK ? EFI_SUCCESS : EFI_VOLUME_CORRUPTED);
+}
+
+static enum step_return
+bzip2_step(decomp_state *dctx, uint8_t *buf, size_t len, size_t offset)
+{
+ bz_stream *strm = &dctx->bzstrm;
+ size_t outlen = dctx->buf_end - dctx->buf_cur;
+
+ strm->next_in = buf;
+ strm->avail_in = len;
+ strm->next_out = dctx->buf_cur;
+ strm->avail_out = outlen;
+
+ int ret = BZ2_bzDecompress(strm);
+ dctx->buf_cur += outlen - strm->avail_out;
+
+ if (ret == BZ_STREAM_END)
+ return (done);
+ if (ret != Z_OK)
+ return (err);
+ if (dctx->buf_cur < dctx->buf_end) /* Have output space */
+ return (ok);
+
+ /*
+ * We're out of space, grow the buffer and try again if there's buffer
+ * space. We try again recursively since we know that will usually go
+ * only 1 deep.
+ */
+ if (EFI_ERROR(grow_buffer(dctx)))
+ return (err);
+ if (strm->avail_in == 0)
+ return (ok);
+ size_t consumed = len - strm->avail_in;
+ return (bzip2_step(dctx, buf + consumed, strm->avail_in, offset + consumed));
+}
+
+static void
+bzip2_fini(decomp_state *dctx, bool flush)
+{
+ BZ2_bzDecompressEnd(&dctx->bzstrm);
+ if (!flush)
+ return;
+ free_buffer(dctx);
+}
+
+/*
+ * ZSTD supprot
+ */
+#ifdef LOADER_ZFS_SUPPORT
+static EFI_STATUS
+zstd_init(decomp_state *dctx, uint8_t *first_buf, size_t buflen, size_t size_hint)
+{
+ unsigned long long size = ZSTD_getFrameContentSize(first_buf, buflen);
+ if (size == ZSTD_CONTENTSIZE_ERROR)
+ return (EFI_VOLUME_CORRUPTED);
+ if (size == ZSTD_CONTENTSIZE_UNKNOWN)
+ dctx->size = max(size_hint * 4, M(64)); /* Guess 4x compression or 64M */
+ else
+ dctx->size = size; /* We know the size */
+ EFI_STATUS status = alloc_buffer(dctx, dctx->size);
+ if (EFI_ERROR(status))
+ return (status);
+
+ dctx->zstdstrm = ZSTD_createDStream();
+ if (dctx->zstdstrm == NULL)
+ return (EFI_OUT_OF_RESOURCES);
+ if (ZSTD_isError(ZSTD_initDStream(dctx->zstdstrm))) {
+ ZSTD_freeDStream(dctx->zstdstrm);
+ dctx->zstdstrm = NULL;
+ return (EFI_OUT_OF_RESOURCES);
+ }
+ return (EFI_SUCCESS);
+}
+
+static enum step_return
+zstd_step(decomp_state *dctx, uint8_t *buf, size_t len, size_t offset)
+{
+ size_t outlen = dctx->buf_end - dctx->buf_cur;
+ ZSTD_inBuffer inbuf = { buf, len, 0 };
+ ZSTD_outBuffer outbuf = { dctx->buf_cur, outlen, 0 };
+ size_t ret;
+
+ ret = ZSTD_decompressStream(dctx->zstdstrm, &outbuf, &inbuf);
+ dctx->buf_cur += outbuf.pos;
+
+ if (ZSTD_isError(ret))
+ return (err);
+ if (ret == 0)
+ return (done);
+ if (dctx->buf_cur < dctx->buf_end) /* Have output space */
+ return (ok);
+
+ /*
+ * We're out of space, grow the buffer and try again if there's buffer
+ * space. We try again recursively since we know that will usually go
+ * only 1 deep.
+ */
+ if (EFI_ERROR(grow_buffer(dctx)))
+ return (err);
+ if (inbuf.size == inbuf.pos)
+ return (ok);
+ return (zstd_step(dctx, buf + inbuf.pos, inbuf.size - inbuf.pos, offset + inbuf.pos));
+}
+
+static void
+zstd_fini(decomp_state *dctx, bool flush)
+{
+ ZSTD_freeDStream(dctx->zstdstrm);
+ if (!flush)
+ return;
+ free_buffer(dctx);
+}
+#endif
+
+/*
+ * No / Unknown decompression fallback
+ */
+static EFI_STATUS
+null_init(decomp_state *dctx, uint8_t *first_buf, size_t buflen, size_t size_hint)
+{
+ dctx->size = size_hint;
+ return (alloc_buffer(dctx, size_hint));
+}
+
+static enum step_return
+null_step(decomp_state *dctx, uint8_t *buf, size_t len, size_t offset)
+{
+ size_t end = offset + len;
+
+ if (end > dctx->size) {
+ printf("Too much data recieved!");
+ return (err);
+ }
+
+ CHAR8 *src = buf;
+ CHAR8 *dst = (void*)(dctx->buf + offset);
+ BS->CopyMem(dst, src, len);
+ return (end == dctx->size ? done : ok);
+}
+
+static void
+null_fini(decomp_state *dctx, bool flush)
+{
+ if (!flush)
+ return;
+ free_buffer(dctx);
+}
+
+decomp_state *
+decomp_init(uint8_t *buf, size_t buflen, size_t size_hint)
+{
+ decomp_state *dctx;
+
+ dctx = malloc(sizeof(*dctx));
+ memset(dctx, 0, sizeof(*dctx));
+ dctx->type = what_compressed(buf, buflen);
+ switch (dctx->type) {
+ case zlib:
+ dctx->init = zlib_init;
+ dctx->step = zlib_step;
+ dctx->fini = zlib_fini;
+ break;
+ case bzip2:
+ dctx->init = bzip2_init;
+ dctx->step = bzip2_step;
+ dctx->fini = bzip2_fini;
+ break;
+#ifdef LOADER_ZFS_SUPPORT
+ case zstd:
+ dctx->init = zstd_init;
+ dctx->step = zstd_step;
+ dctx->fini = zstd_fini;
+ break;
+#endif
+ case none:
+ dctx->init = null_init;
+ dctx->step = null_step;
+ dctx->fini = null_fini;
+ break;
+ default:
+ return (NULL);
+ }
+
+ if (EFI_ERROR(dctx->init(dctx, buf, buflen, size_hint))) {
+ free(dctx);
+ dctx = NULL;
+ }
+ return (dctx);
+}
+
+enum step_return
+decomp_step(decomp_state *dctx, uint8_t *buf, size_t len, size_t offset)
+{
+ return (dctx->step(dctx, buf, len, offset));
+}
+
+void
+decomp_fini(decomp_state *dctx, bool flush)
+{
+ return (dctx->fini(dctx, flush));
+}
+
+EFI_PHYSICAL_ADDRESS
+decomp_buffer(decomp_state *dctx)
+{
+ if (dctx == NULL)
+ return (0);
+ return (dctx->buf);
+}
+
+size_t
+decomp_buffer_length(decomp_state *dctx)
+{
+ if (dctx == NULL)
+ return (0);
+ return ((void *)dctx->buf_cur - (void *)dctx->buf);
+}
diff --git a/stand/efi/loader/decompress.h b/stand/efi/loader/decompress.h
new file mode 100644
index 000000000000..43c48078f822
--- /dev/null
+++ b/stand/efi/loader/decompress.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2026 Netflix, Inc. Written by Warner Losh
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+enum compression { none, zlib, bzip2, zstd };
+enum step_return { ok, done, err };
+
+typedef struct decomp_state decomp_state;
+
+decomp_state *decomp_init(uint8_t *buf, size_t buflen, size_t size_hint);
+enum step_return decomp_step(decomp_state *dctx, uint8_t *buf, size_t len, size_t offset);
+void decomp_fini(decomp_state *dctx, bool flush);
+EFI_PHYSICAL_ADDRESS decomp_buffer(decomp_state *dctx);
+size_t decomp_buffer_length(decomp_state *dctx);
+
diff --git a/stand/efi/loader/loader_efi.h b/stand/efi/loader/loader_efi.h
index be991eeb9573..c53edb639ad5 100644
--- a/stand/efi/loader/loader_efi.h
+++ b/stand/efi/loader/loader_efi.h
@@ -59,6 +59,8 @@ void * efi_translate(vm_offset_t ptr);
void efi_copy_finish(void);
void efi_copy_finish_nop(void);
+void maybe_download_ramdisk(int argc, CHAR16 **argv);
+
#if defined(__amd64__) || defined(__i386__)
/* Need this to setup page tables */
extern EFI_PHYSICAL_ADDRESS staging;
diff --git a/stand/efi/loader/main.c b/stand/efi/loader/main.c
index 050e802181b1..cc7a9c4ac814 100644
--- a/stand/efi/loader/main.c
+++ b/stand/efi/loader/main.c
@@ -1319,6 +1319,14 @@ main(int argc, CHAR16 *argv[])
*/
bcache_init(32768, 512);
+ /*
+ * Scan the command line args for memdisk=<url> and download that image
+ * to install as a ramdisk. This needs to be done before we scan the
+ * handles because it installs a handle and creates the right ACPI
+ * tables for the kernel to find it.
+ */
+ maybe_download_ramdisk(argc, argv);
+
/*
* Scan the BLOCK IO MEDIA handles then
* march through the device switch probing for things.
@@ -1329,6 +1337,11 @@ main(int argc, CHAR16 *argv[])
"failures\n", i);
}
+ /*
+ * Scan all the VirtualDisks, passing them along to the FreeBSD kernel.
+ */
+ efiblk_memdisk_preload();
+
devinit();
/*
diff --git a/stand/efi/loader/memdisk.c b/stand/efi/loader/memdisk.c
new file mode 100644
index 000000000000..8d34d3ceae42
--- /dev/null
+++ b/stand/efi/loader/memdisk.c
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2026 Netflix, Inc. Written by Warner Losh
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Derived from memdisk_uefi.c
+ * Copyright 2025 Richard Russo
+ * SPDX-License-Identifier: BSD-2-Clause-Patent
+ */
+
+#include "loader_efi.h"
+#include <efilib.h>
+#include <Protocol/RamDisk.h>
+#include "decompress.h"
+#include <ipxe_download.h>
+#include <sys/_param.h>
+
+#define ULL(x) ((unsigned long long)(x))
+
+static EFI_GUID ipxeGuid = IPXE_DOWNLOAD_PROTOCOL_GUID;
+static EFI_GUID ramdiskGuid = EFI_RAM_DISK_PROTOCOL_GUID;
+static EFI_GUID virtual_disk_guid = EFI_VIRTUAL_DISK_GUID;
+static EFI_GUID virtual_cd_guid = EFI_VIRTUAL_CD_GUID;
+
+static IPXE_DOWNLOAD_PROTOCOL *ipxe_download;
+static EFI_RAM_DISK_PROTOCOL *ram_disk;
+
+struct dl_state;
+typedef struct dl_state dl_state;
+
+static struct dl_state
+{
+ bool in_progress;
+ size_t size;
+ EFI_STATUS status;
+ decomp_state *dctx;
+} dl;
+
+static void
+download_cleanup(dl_state *ctx)
+{
+ if (ctx->dctx)
+ decomp_fini(ctx->dctx, true);
+ ctx->in_progress = false;
+}
+
+static EFI_STATUS EFIAPI
+download_data(IN VOID *Context, IN VOID *Buffer, IN UINTN BufferLength, IN UINTN FileOffset)
+{
+ dl_state *ctx = Context;
+ decomp_state *dctx = ctx->dctx;
+
+ /*
+ * Make a note of the size when we're hinted about it. But once
+ * we start the download, ignore the hints.
+ */
+ if (ctx->size == 0 && BufferLength == 0) {
+ printf("We know we will download %llu bytes\n", ULL(FileOffset));
+ ctx->size = FileOffset;
+ ctx->status = EFI_SUCCESS;
+ return (EFI_SUCCESS);
+ }
+
+ /*
+ * Peek into the first chunk to see the format of the data.
+ */
+ if (FileOffset == 0) {
+ dctx = decomp_init((uint8_t *)Buffer, (size_t)BufferLength, ctx->size);
+ if (dctx == NULL) {
+ ctx->in_progress = false;
+ ctx->status = EFI_VOLUME_CORRUPTED;
+ return (ctx->status);
+ }
+ ctx->dctx = dctx;
+ }
+
+ enum step_return sr = decomp_step(dctx, Buffer, BufferLength, FileOffset);
+ if (sr == err) {
+ printf("Error on download\n");
+ decomp_fini(dctx, true);
+ return (EFI_VOLUME_CORRUPTED);
+ }
+
+ unsigned long long sofar = FileOffset + BufferLength;
+#define MB 1000000
+ if (sofar / MB != FileOffset / MB) {
+ if (ctx->size)
+ printf("%dMB / %dMB (%d%%)\r",
+ (int)(sofar / MB),
+ (int)(ctx->size / MB),
+ (int)(100 * sofar / ctx->size));
+ else
+ printf("%dMB\r", (int)(sofar / MB));
+ }
+ return (EFI_SUCCESS);
+}
+
+static void EFIAPI
+download_finish(IN VOID *Context, IN EFI_STATUS Status)
+{
+ dl_state *ctx = Context;
+
+ ctx->in_progress = false;
+ ctx->status = Status;
+ if (ctx->dctx)
+ decomp_fini(ctx->dctx, EFI_ERROR(Status));
+}
+
+static void
+do_download_ramdisk(CHAR8 *url, bool is_disk)
+{
+ EFI_STATUS Status;
+ EFI_GUID disk_type = is_disk ? virtual_disk_guid : virtual_cd_guid;
+ EFI_DEVICE_PATH_PROTOCOL *ram_disk_path;
+ IPXE_DOWNLOAD_FILE token;
+ dl_state *ctx = &dl;
+
+ Status = BS->LocateProtocol(&ipxeGuid, NULL, (void**)&ipxe_download);
+ if (EFI_ERROR(Status))
+ return; /* most uses won't have this, don't whine */
+ Status = BS->LocateProtocol(&ramdiskGuid, NULL, (void**)&ram_disk);
+ if (EFI_ERROR(Status))
+ return; /* XXX whine about it? */
+
+ printf("Downloading %s as a %s\n", url, is_disk ? "disk" : "cd");
+ ctx->in_progress = true;
+ Status = ipxe_download->Start(ipxe_download, url, download_data, download_finish,
+ &dl, &token);
+ if (EFI_ERROR(Status)) {
+ printf("Couldn't start download %u\n", (unsigned)Status);
+ download_cleanup(ctx);
+ return;
+ }
+ while (ctx->in_progress) {
+ ipxe_download->Poll(ipxe_download);
+ }
+ if (EFI_ERROR(ctx->status)) {
+ printf("Download had error %u\n", (unsigned)ctx->status);
+ download_cleanup(ctx);
+ return;
+ }
+ if (ctx->size == 0) {
+ printf("Nothing downloaded\n");
+ download_cleanup(ctx);
+ return;
+ }
+
+ printf("\nDownloaded %llu bytes, actual size %llu -- registering ramdisk\n",
+ ULL(ctx->size), ULL(decomp_buffer_length(ctx->dctx)));
+
+ /*
+ * Register the RamDisk with UEFI. This registers it so the rest of the
+ * boot loader can see it as a block device.
+ */
+ Status = ram_disk->Register(decomp_buffer(ctx->dctx), decomp_buffer_length(ctx->dctx),
+ &disk_type, NULL, &ram_disk_path);
+ if (EFI_ERROR(Status)) {
+ printf("failed to register ram disk %u\n", (unsigned)Status);
+ download_cleanup(ctx);
+ return;
+ }
+
+ CHAR16 *text = efi_devpath_name(ram_disk_path);
+ if (text != NULL) {
+ CHAR8 uefi_path[1024];
+ printf("Installed RAM disk as %S\n", text);
+
+ cpy16to8(text, uefi_path, sizeof(uefi_path));
+ setenv("uefi_ignore_boot_mgr", "true", 1);
+ setenv("uefi_rootdev", uefi_path, 1);
+ efi_free_devpath_name(text);
+ } else {
+ printf("Installed RAM disk to unknown device type\n");
+ }
+}
+
+/*
+ * Scan the command line for memdisk=url or memcd=url. Do nothing if that's not
+ * present, otherwise try to download that image.
+ *
+ * Open Question: Do we want some way to chain boot into the /boot/loader.efi or
+ * \efi\boot\bootXXXXX.efi inside the ram disk we load? If so, how do we keep
+ * from infinite chainbooting? Also, I don't understand the load it but don't save
+ * it option...
+ */
+void
+maybe_download_ramdisk(int argc, CHAR16 **argv)
+{
+ char var[256];
+
+ for (int i = 0; i < argc; i++) {
+ cpy16to8(argv[i], var, sizeof(var));
+ if (strncmp(var, "memdisk=", 8) == 0) {
+ do_download_ramdisk(var + 8, true);
+ return;
+ }
+ if (strncmp(var, "memcd=", 6) == 0) {
+ do_download_ramdisk(var + 6, false);
+ return;
+ }
+ }
+ return;
+}