bhyve: Make boot ROM handling more consistent

- On amd64, deprecate lpc.bootrom and lpc.bootvars.  Use top-level
  config variables instead.
- Introduce a generic predicate which can be used to determine whether
  the guest has a boot ROM.

Reviewed by:	corvink, jhb
MFC after:	2 weeks
Sponsored by:	Innovate UK
Differential Revision:	https://reviews.freebsd.org/D46282

usr.sbin/bhyve/amd64/bhyverun_machdep.c

@@ -37,6 +37,7 @@
 #include "acpi.h"
 #include "atkbdc.h"
 #include "bhyverun.h"
+#include "bootrom.h"
 #include "config.h"
 #include "debug.h"
 #include "e820.h"
@@ -241,6 +242,18 @@ bhyve_optparse(int argc, char **argv)
 			bhyve_usage(1);
 		}
 	}
+
+	/* Handle backwards compatibility aliases in config options. */
+	if (get_config_value("lpc.bootrom") != NULL &&
+	    get_config_value("bootrom") == NULL) {
+		warnx("lpc.bootrom is deprecated, use '-o bootrom' instead");
+		set_config_value("bootrom", get_config_value("lpc.bootrom"));
+	}
+	if (get_config_value("lpc.bootvars") != NULL &&
+	    get_config_value("bootvars") == NULL) {
+		warnx("lpc.bootvars is deprecated, use '-o bootvars' instead");
+		set_config_value("bootvars", get_config_value("lpc.bootvars"));
+	}
 }
 
 void
@@ -291,7 +304,7 @@ bhyve_start_vcpu(struct vcpu *vcpu, bool bsp)
 	int error;
 
 	if (bsp) {
-		if (lpc_bootrom()) {
+		if (bootrom_boot()) {
 			error = vm_set_capability(vcpu,
 			    VM_CAP_UNRESTRICTED_GUEST, 1);
 			if (error != 0) {
@@ -332,6 +345,9 @@ bhyve_init_platform(struct vmctx *ctx, struct vcpu *bsp __unused)
 	rtc_init(ctx);
 	sci_init(ctx);
 	error = e820_init(ctx);
+	if (error != 0)
+		return (error);
+	error = bootrom_loadrom(ctx);
 	if (error != 0)
 		return (error);
 
@@ -355,7 +371,7 @@ bhyve_init_platform_late(struct vmctx *ctx, struct vcpu *bsp __unused)
 	if (error != 0)
 		return (error);
 
-	if (lpc_bootrom() && strcmp(lpc_fwcfg(), "bhyve") == 0)
+	if (bootrom_boot() && strcmp(lpc_fwcfg(), "bhyve") == 0)
 		fwctl_init();
 
 	if (get_config_bool("acpi_tables")) {

usr.sbin/bhyve/amd64/ioapic.c

@@ -33,6 +33,7 @@
 #include <machine/vmm.h>
 #include <vmmapi.h>
 
+#include "bootrom.h"
 #include "ioapic.h"
 #include "pci_emul.h"
 #include "pci_lpc.h"
@@ -72,7 +73,7 @@ ioapic_pci_alloc_irq(struct pci_devinst *pi)
 
 	if (pci_pins == 0)
 		return (-1);
-	if (lpc_bootrom()) {
+	if (bootrom_boot()) {
 		/* For external bootrom use fixed mapping. */
 		return (16 + (4 + pi->pi_slot + pi->pi_lintr.pin) % 8);
 	}

usr.sbin/bhyve/amd64/pci_irq.c

@@ -38,6 +38,7 @@
 #include <vmmapi.h>
 
 #include "acpi.h"
+#include "bootrom.h"
 #include "inout.h"
 #include "ioapic.h"
 #include "pci_emul.h"
@@ -205,7 +206,7 @@ pirq_alloc_pin(struct pci_devinst *pi)
 
 	pirq_cold = 0;
 
-	if (lpc_bootrom()) {
+	if (bootrom_boot()) {
 		/* For external bootrom use fixed mapping. */
 		best_pin = (4 + pi->pi_slot + pi->pi_lintr.pin) % 8;
 	} else {

usr.sbin/bhyve/amd64/pci_lpc.c

@@ -104,7 +104,7 @@ lpc_device_parse(const char *opts)
 			if (romfile == NULL) {
 				errx(4, "invalid bootrom option \"%s\"", opts);
 			}
-			set_config_value("lpc.bootrom", romfile);
+			set_config_value("bootrom", romfile);
 
 			varfile = strsep(&str, ",");
 			if (varfile == NULL) {
@@ -112,7 +112,7 @@ lpc_device_parse(const char *opts)
 				goto done;
 			}
 			if (strchr(varfile, '=') == NULL) {
-				set_config_value("lpc.bootvars", varfile);
+				set_config_value("bootvars", varfile);
 			} else {
 				/* varfile doesn't exist, it's another config
 				 * option */
@@ -182,13 +182,6 @@ lpc_print_supported_devices(void)
 	printf("%s\n", pctestdev_getname());
 }
 
-const char *
-lpc_bootrom(void)
-{
-
-	return (get_config_value("lpc.bootrom"));
-}
-
 const char *
 lpc_fwcfg(void)
 {
@@ -256,14 +249,6 @@ lpc_init(struct vmctx *ctx)
 	const char *backend, *name;
 	char *node_name;
 	int unit, error;
-	const nvlist_t *nvl;
-
-	nvl = find_config_node("lpc");
-	if (nvl != NULL && nvlist_exists(nvl, "bootrom")) {
-		error = bootrom_loadrom(ctx, nvl);
-		if (error)
-			return (error);
-	}
 
 	/* COM1 and COM2 */
 	for (unit = 0; unit < LPC_UART_NUM; unit++) {

usr.sbin/bhyve/amd64/pci_lpc.h

@@ -69,7 +69,6 @@ int	lpc_device_parse(const char *opt);
 void    lpc_print_supported_devices(void);
 char	*lpc_pirq_name(int pin);
 void	lpc_pirq_routed(void);
-const char *lpc_bootrom(void);
 const char *lpc_fwcfg(void);
 
 #endif

usr.sbin/bhyve/bhyve_config.5

@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd November 20, 2023
+.Dd August 13, 2024
 .Dt BHYVE_CONFIG 5
 .Os
 .Sh NAME
@@ -120,6 +120,17 @@ The value must be formatted as described in
 .Xr expand_number 3 .
 .It Va memory.wired Ta bool Ta false Ta
 Wire guest memory.
+.It Va bootrom Ta path Ta Ta
+Path to a boot ROM.
+During initialization of the guest, the contents of this file are copied into
+the guest's memory.
+If a boot ROM is present, a firmware interface device is
+also enabled for use by the boot ROM.
+.It Va bootvars Ta path Ta Ta
+Path to boot VARS.
+The contents of this file are copied beneath the boot ROM.
+Firmware can write to it to save variables.
+All variables will be persistent even on reboots of the guest.
 .It Va acpi_tables Ta bool Ta true Ta
 Generate ACPI tables.
 .It Va acpi_tables_in_memory Ta bool Ta true Ta
@@ -550,17 +561,6 @@ The following nodes are available under
 .Va lpc :
 .Bl -column "pc-testdev" "Format" "Default"
 .It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
-.It Va bootrom Ta path Ta Ta
-Path to a boot ROM.
-The contents of this file are copied into the guest's
-memory ending just before the 4GB physical address.
-If a boot ROM is present, a firmware interface device is
-also enabled for use by the boot ROM.
-.It Va bootvars Ta path Ta Ta
-Path to boot VARS.
-The contents of this file are copied beneath the boot ROM.
-Firmware can write to it to save variables.
-All variables will be persistent even on reboots of the guest.
 .It Va com1 Ta node Ta Ta
 Settings for the COM1 serial port device.
 .It Va com2 Ta node Ta Ta

usr.sbin/bhyve/bhyverun.c

@@ -525,12 +525,7 @@ do_open(const char *vmname)
 
 	reinit = false;
 
-#ifdef __amd64__
-	romboot = lpc_bootrom() != NULL;
-#else
-	romboot = true;
-#endif
-
+	romboot = bootrom_boot();
 	error = vm_create(vmname);
 	if (error) {
 		if (errno == EEXIST) {

usr.sbin/bhyve/bootrom.c

@@ -192,7 +192,7 @@ bootrom_alloc(struct vmctx *ctx, size_t len, int prot, int flags,
 }
 
 int
-bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl)
+bootrom_loadrom(struct vmctx *ctx)
 {
 	struct stat sbuf;
 	ssize_t rlen;
@@ -204,9 +204,9 @@ bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl)
 	rv = -1;
 	varfd = -1;
 
-	bootrom = get_config_value_node(nvl, "bootrom");
+	bootrom = get_config_value("bootrom");
 	if (bootrom == NULL) {
-		return (-1);
+		return (0);
 	}
 
 	/*
@@ -235,7 +235,7 @@ bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl)
 
 	rom_size = sbuf.st_size;
 
-	varfile = get_config_value_node(nvl, "bootvars");
+	varfile = get_config_value("bootvars");
 	var_size = 0;
 	if (varfile != NULL) {
 		varfd = open(varfile, O_RDWR);
@@ -314,3 +314,12 @@ done:
 	free(romfile);
 	return (rv);
 }
+
+/*
+ * Are we relying on a bootrom to initialize the guest's CPU context?
+ */
+bool
+bootrom_boot(void)
+{
+	return (get_config_value("bootrom") != NULL);
+}

usr.sbin/bhyve/bootrom.h

@@ -45,6 +45,7 @@ enum {
 };
 int bootrom_alloc(struct vmctx *ctx, size_t len, int prot, int flags,
     char **region_out, uint64_t *gpa_out);
-int bootrom_loadrom(struct vmctx *ctx, const nvlist_t *nvl);
+bool bootrom_boot(void);
+int bootrom_loadrom(struct vmctx *ctx);
 
 #endif