Restructure memory allocation in bhyve to support "devmem".

devmem is used to represent MMIO devices like the boot ROM or a VESA framebuffer
where doing a trap-and-emulate for every access is impractical. devmem is a
hybrid of system memory (sysmem) and emulated device models.

devmem is mapped in the guest address space via nested page tables similar
to sysmem. However the address range where devmem is mapped may be changed
by the guest at runtime (e.g. by reprogramming a PCI BAR). Also devmem is
usually mapped RO or RW as compared to RWX mappings for sysmem.

Each devmem segment is named (e.g. "bootrom") and this name is used to
create a device node for the devmem segment (e.g. /dev/vmm/testvm.bootrom).
The device node supports mmap(2) and this decouples the host mapping of
devmem from its mapping in the guest address space (which can change).

Reviewed by:	tychon
Discussed with:	grehan
Differential Revision:	https://reviews.freebsd.org/D2762
MFC after:	4 weeks

1 files changed, 24 insertions, 3 deletions

diff --git a/usr.sbin/bhyve/pci_lpc.c b/usr.sbin/bhyve/pci_lpc.c
index e98b141..2203a00 100644
--- a/usr.sbin/bhyve/pci_lpc.c
+++ b/usr.sbin/bhyve/pci_lpc.c
@@ -40,6 +40,7 @@ __FBSDID("$FreeBSD$");
 #include <vmmapi.h>
 
 #include "acpi.h"
+#include "bootrom.h"
 #include "inout.h"
 #include "pci_emul.h"
 #include "pci_irq.h"
@@ -62,6 +63,8 @@ SYSRES_IO(NMISC_PORT, 1);
 
 static struct pci_devinst *lpc_bridge;
 
+static const char *romfile;
+
 #define	LPC_UART_NUM	2
 static struct lpc_uart_softc {
 	struct uart_softc *uart_softc;
@@ -76,7 +79,7 @@ static const char *lpc_uart_names[LPC_UART_NUM] = { "COM1", "COM2" };
 /*
  * LPC device configuration is in the following form:
  * <lpc_device_name>[,<options>]
- * For e.g. "com1,stdio"
+ * For e.g. "com1,stdio" or "bootrom,/var/romfile"
  */
 int
 lpc_device_parse(const char *opts)
@@ -88,6 +91,11 @@ lpc_device_parse(const char *opts)
 	str = cpy = strdup(opts);
 	lpcdev = strsep(&str, ",");
 	if (lpcdev != NULL) {
+		if (strcasecmp(lpcdev, "bootrom") == 0) {
+			romfile = str;
+			error = 0;
+			goto done;
+		}
 		for (unit = 0; unit < LPC_UART_NUM; unit++) {
 			if (strcasecmp(lpcdev, lpc_uart_names[unit]) == 0) {
 				lpc_uart_softc[unit].opts = str;
@@ -104,6 +112,13 @@ done:
 	return (error);
 }
 
+const char *
+lpc_bootrom(void)
+{
+
+	return (romfile);
+}
+
 static void
 lpc_uart_intr_assert(void *arg)
 {
@@ -156,13 +171,19 @@ lpc_uart_io_handler(struct vmctx *ctx, int vcpu, int in, int port, int bytes,
 }
 
 static int
-lpc_init(void)
+lpc_init(struct vmctx *ctx)
 {
 	struct lpc_uart_softc *sc;
 	struct inout_port iop;
 	const char *name;
 	int unit, error;
 
+	if (romfile != NULL) {
+		error = bootrom_init(ctx, romfile);
+		if (error)
+			return (error);
+	}
+
 	/* COM1 and COM2 */
 	for (unit = 0; unit < LPC_UART_NUM; unit++) {
 		sc = &lpc_uart_softc[unit];
@@ -379,7 +400,7 @@ pci_lpc_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
 		return (-1);
 	}
 
-	if (lpc_init() != 0)
+	if (lpc_init(ctx) != 0)
 		return (-1);
 
 	/* initialize config space */