git: 866036f46c6e - main - bhyve: Support a _VARS.fd file for bootrom
Date: Sun, 12 Dec 2021 15:08:26 UTC
The branch main has been updated by bcran:
URL: https://cgit.FreeBSD.org/src/commit/?id=866036f46c6e8884cc7a2aa029408366ede40a23
commit 866036f46c6e8884cc7a2aa029408366ede40a23
Author: Rebecca Cran <bcran@FreeBSD.org>
AuthorDate: 2021-11-28 16:34:33 +0000
Commit: Rebecca Cran <bcran@FreeBSD.org>
CommitDate: 2021-12-12 15:07:27 +0000
bhyve: Support a _VARS.fd file for bootrom
OVMF creates two separate .fd files, a _CODE.fd file containing
the UEFI code, and a _VARS.fd file containing a template of an
empty UEFI variable store.
OVMF decides to write variables to the memory range just below the
boot rom code if it detects a CFI flash device. So here we add
just the barest facsimile of CFI command handling to bootrom.c
that is needed to placate OVMF.
Submitted by: D Scott Phillips <d.scott.phillips@intel.com>
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D19976
MFC After: 1 week
---
usr.sbin/bhyve/bhyve.8 | 23 ++++++++-
usr.sbin/bhyve/bootrom.c | 132 ++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 145 insertions(+), 10 deletions(-)
diff --git a/usr.sbin/bhyve/bhyve.8 b/usr.sbin/bhyve/bhyve.8
index 3b7bf6b65467..fe4eb3ffaaeb 100644
--- a/usr.sbin/bhyve/bhyve.8
+++ b/usr.sbin/bhyve/bhyve.8
@@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd October 13, 2021
+.Dd November 28, 2021
.Dt BHYVE 8
.Os
.Sh NAME
@@ -500,10 +500,15 @@ Use the host TTY device for serial port I/O.
.Pp
Boot ROM device backends:
.Bl -tag -width 10n
-.It Ar romfile
+.It Ar romfile Ns Op Cm \&, Ns Ar varfile
Map
.Ar romfile
in the guest address space reserved for boot firmware.
+If
+.Ar varfile
+is provided, that file is also mapped in the boot firmware guest
+address space, and any modifications the guest makes will be saved
+to that file.
.El
.Pp
Pass-through device backends:
@@ -916,6 +921,20 @@ bhyve -c 2 -m 4G -w -H \\
-l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \\
uefivm
.Ed
+.Pp
+Run a UEFI virtual machine with a VARS file to save EFI variables.
+Note that
+.Nm
+will write guest modifications to the given VARS file.
+Be sure to create a per-guest copy of the template VARS file from
+.Pa /usr .
+.Bd -literal -offset indent
+bhyve -c 2 -m 4g -w -H \\
+ -s 0,hostbridge \\
+ -s 31,lpc -p com1,stdio \\
+ -l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI_CODE.fd,BHYVE_UEFI_VARS.fd
+ uefivm
+.Ed
.Sh SEE ALSO
.Xr bhyve 4 ,
.Xr netgraph 4 ,
diff --git a/usr.sbin/bhyve/bootrom.c b/usr.sbin/bhyve/bootrom.c
index 38a50490eb0b..757ec07d4a54 100644
--- a/usr.sbin/bhyve/bootrom.c
+++ b/usr.sbin/bhyve/bootrom.c
@@ -39,14 +39,17 @@ __FBSDID("$FreeBSD$");
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdbool.h>
#include <vmmapi.h>
+
#include "bhyverun.h"
#include "bootrom.h"
#include "debug.h"
+#include "mem.h"
#define BOOTROM_SIZE (16 * 1024 * 1024) /* 16 MB */
@@ -64,6 +67,56 @@ static vm_paddr_t gpa_base; /* GPA of low end of region. */
static vm_paddr_t gpa_allocbot; /* Low GPA of free region. */
static vm_paddr_t gpa_alloctop; /* High GPA, minus 1, of free region. */
+#define CFI_BCS_WRITE_BYTE 0x10
+#define CFI_BCS_CLEAR_STATUS 0x50
+#define CFI_BCS_READ_STATUS 0x70
+#define CFI_BCS_READ_ARRAY 0xff
+
+static struct bootrom_var_state {
+ uint8_t *mmap;
+ uint64_t gpa;
+ off_t size;
+ uint8_t cmd;
+} var = { NULL, 0, 0, CFI_BCS_READ_ARRAY };
+
+/*
+ * Emulate just those CFI basic commands that will convince EDK II
+ * that the Firmware Volume area is writable and persistent.
+ */
+static int
+bootrom_var_mem_handler(struct vmctx *ctx, int vcpu, int dir, uint64_t addr,
+ int size, uint64_t *val, void *arg1, long arg2)
+{
+ off_t offset;
+
+ offset = addr - var.gpa;
+ if (offset + size > var.size || offset < 0 || offset + size <= offset)
+ return (EINVAL);
+
+ if (dir == MEM_F_WRITE) {
+ switch (var.cmd) {
+ case CFI_BCS_WRITE_BYTE:
+ memcpy(var.mmap + offset, val, size);
+ var.cmd = CFI_BCS_READ_ARRAY;
+ break;
+ default:
+ var.cmd = *(uint8_t *)val;
+ }
+ } else {
+ switch (var.cmd) {
+ case CFI_BCS_CLEAR_STATUS:
+ case CFI_BCS_READ_STATUS:
+ memset(val, 0, size);
+ var.cmd = CFI_BCS_READ_ARRAY;
+ break;
+ default:
+ memcpy(val, var.mmap + offset, size);
+ break;
+ }
+ }
+ return (0);
+}
+
void
init_bootrom(struct vmctx *ctx)
{
@@ -142,10 +195,16 @@ bootrom_loadrom(struct vmctx *ctx, const char *romfile)
{
struct stat sbuf;
ssize_t rlen;
- char *ptr;
- int fd, i, rv;
+ off_t rom_size, var_size, total_size;
+ char *ptr, *varfile;
+ int fd, varfd, i, rv;
rv = -1;
+ varfd = -1;
+
+ varfile = strdup(romfile);
+ romfile = strsep(&varfile, ",");
+
fd = open(romfile, O_RDONLY);
if (fd < 0) {
EPRINTLN("Error opening bootrom \"%s\": %s",
@@ -153,19 +212,56 @@ bootrom_loadrom(struct vmctx *ctx, const char *romfile)
goto done;
}
- if (fstat(fd, &sbuf) < 0) {
+ if (varfile != NULL) {
+ varfd = open(varfile, O_RDWR);
+ if (varfd < 0) {
+ fprintf(stderr, "Error opening bootrom variable file "
+ "\"%s\": %s\n", varfile, strerror(errno));
+ goto done;
+ }
+ }
+
+ if (fstat(fd, &sbuf) < 0) {
EPRINTLN("Could not fstat bootrom file \"%s\": %s",
- romfile, strerror(errno));
+ romfile, strerror(errno));
goto done;
- }
+ }
+
+ rom_size = sbuf.st_size;
+ if (varfd < 0) {
+ var_size = 0;
+ } else {
+ if (fstat(varfd, &sbuf) < 0) {
+ fprintf(stderr, "Could not fstat bootrom variable file \"%s\": %s\n",
+ varfile, strerror(errno));
+ goto done;
+ }
+ var_size = sbuf.st_size;
+ }
+
+ if (var_size > BOOTROM_SIZE ||
+ (var_size != 0 && var_size < PAGE_SIZE)) {
+ fprintf(stderr, "Invalid bootrom variable size %ld\n",
+ var_size);
+ goto done;
+ }
+
+ total_size = rom_size + var_size;
+
+ if (total_size > BOOTROM_SIZE) {
+ fprintf(stderr, "Invalid bootrom and variable aggregate size "
+ "%ld\n", total_size);
+ goto done;
+ }
/* Map the bootrom into the guest address space */
- if (bootrom_alloc(ctx, sbuf.st_size, PROT_READ | PROT_EXEC,
- BOOTROM_ALLOC_TOP, &ptr, NULL) != 0)
+ if (bootrom_alloc(ctx, rom_size, PROT_READ | PROT_EXEC,
+ BOOTROM_ALLOC_TOP, &ptr, NULL) != 0) {
goto done;
+ }
/* Read 'romfile' into the guest address space */
- for (i = 0; i < sbuf.st_size / PAGE_SIZE; i++) {
+ for (i = 0; i < rom_size / PAGE_SIZE; i++) {
rlen = read(fd, ptr + i * PAGE_SIZE, PAGE_SIZE);
if (rlen != PAGE_SIZE) {
EPRINTLN("Incomplete read of page %d of bootrom "
@@ -173,6 +269,26 @@ bootrom_loadrom(struct vmctx *ctx, const char *romfile)
goto done;
}
}
+
+ if (varfd >= 0) {
+ var.mmap = mmap(NULL, var_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, varfd, 0);
+ if (var.mmap == MAP_FAILED)
+ goto done;
+ var.size = var_size;
+ var.gpa = (gpa_alloctop - var_size) + 1;
+ gpa_alloctop = var.gpa - 1;
+ rv = register_mem(&(struct mem_range){
+ .name = "bootrom variable",
+ .flags = MEM_F_RW,
+ .handler = bootrom_var_mem_handler,
+ .base = var.gpa,
+ .size = var.size,
+ });
+ if (rv != 0)
+ goto done;
+ }
+
rv = 0;
done:
if (fd >= 0)