[block] Describe all SAN devices via ACPI tables

Describe all SAN devices via ACPI tables such as the iBFT.  For tables
that can describe only a single device (i.e. the aBFT and sBFT), one
table is installed per device.  For multi-device tables (i.e. the
iBFT), all devices are described in a single table.

An underlying SAN device connection may be closed at the time that we
need to construct an ACPI table.  We therefore introduce the concept
of an "ACPI descriptor" which enables the SAN boot code to maintain an
opaque pointer to the underlying object, and an "ACPI model" which can
build tables from a list of such descriptors.  This separates the
lifecycles of ACPI descriptions from the lifecycles of the block
device interfaces, and allows for construction of the ACPI tables even
if the block device interface has been closed.

For a multipath SAN device, iPXE will wait until sufficient
information is available to describe all devices but will not wait for
all paths to connect successfully.  For example: with a multipath
iSCSI boot iPXE will wait until at least one path has become available
and name resolution has completed on all other paths.  We do this
since the iBFT has to include IP addresses rather than DNS names.  We
will commence booting without waiting for the inactive paths to either
become available or close; this avoids unnecessary boot delays.

Note that the Linux kernel will refuse to accept an iBFT with more
than two NIC or target structures.  We therefore describe only the
NICs that are actually required in order to reach the described
targets.  Any iBFT with at most two targets is therefore guaranteed to
describe at most two NICs.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 65 insertions, 52 deletions

diff --git a/src/arch/x86/interface/pcbios/int13.c b/src/arch/x86/interface/pcbios/int13.c
index 0bc123d7..b793d730 100644
--- a/src/arch/x86/interface/pcbios/int13.c
+++ b/src/arch/x86/interface/pcbios/int13.c
@@ -1239,13 +1239,14 @@ static void int13_unhook_vector ( void ) {
  * @v drive		Drive number
  * @v uris		List of URIs
  * @v count		Number of URIs
+ * @v flags		Flags
  * @ret drive		Drive number, or negative error
  *
  * Registers the drive with the INT 13 emulation subsystem, and hooks
  * the INT 13 interrupt vector (if not already hooked).
  */
 static int int13_hook ( unsigned int drive, struct uri **uris,
-			unsigned int count ) {
+			unsigned int count, unsigned int flags ) {
 	struct san_device *sandev;
 	struct int13_data *int13;
 	unsigned int natural_drive;
@@ -1267,14 +1268,13 @@ static int int13_hook ( unsigned int drive, struct uri **uris,
 		rc = -ENOMEM;
 		goto err_alloc;
 	}
-	sandev->drive = drive;
 	int13 = sandev->priv;
 	int13->natural_drive = natural_drive;
 
 	/* Register SAN device */
-	if ( ( rc = register_sandev ( sandev ) ) != 0 ) {
+	if ( ( rc = register_sandev ( sandev, drive, flags ) ) != 0 ) {
 		DBGC ( sandev, "INT13 drive %02x could not register: %s\n",
-		       sandev->drive, strerror ( rc ) );
+		       drive, strerror ( rc ) );
 		goto err_register;
 	}
 
@@ -1544,70 +1544,83 @@ static int int13_boot ( unsigned int drive ) {
 	return -ECANCELED; /* -EIMPOSSIBLE */
 }
 
-/** A boot firmware table generated by iPXE */
-union xbft_table {
-	/** ACPI header */
-	struct acpi_description_header acpi;
-	/** Padding */
-	char pad[768];
-};
+/** Maximum size of boot firmware table(s) */
+#define XBFTAB_SIZE 768
+
+/** Alignment of boot firmware table entries */
+#define XBFTAB_ALIGN 16
 
-/** The boot firmware table generated by iPXE */
-static union xbft_table __bss16 ( xbftab ) __attribute__ (( aligned ( 16 ) ));
+/** The boot firmware table(s) generated by iPXE */
+static uint8_t __bss16_array ( xbftab, [XBFTAB_SIZE] )
+	__attribute__ (( aligned ( XBFTAB_ALIGN ) ));
 #define xbftab __use_data16 ( xbftab )
 
+/** Total used length of boot firmware tables */
+static size_t xbftab_used;
+
 /**
- * Describe SAN device for SAN-booted operating system
+ * Install ACPI table
  *
- * @v drive		Drive number
+ * @v acpi		ACPI description header
  * @ret rc		Return status code
  */
-static int int13_describe ( unsigned int drive ) {
-	struct san_device *sandev;
-	struct san_path *sanpath;
+static int int13_install ( struct acpi_header *acpi ) {
 	struct segoff xbft_address;
-	int rc;
-
-	/* Find drive */
-	sandev = sandev_find ( drive );
-	if ( ! sandev ) {
-		DBG ( "INT13 cannot find drive %02x\n", drive );
-		return -ENODEV;
+	struct acpi_header *installed;
+	size_t len;
+
+	/* Check length */
+	len = acpi->length;
+	if ( len > ( sizeof ( xbftab ) - xbftab_used ) ) {
+		DBGC ( acpi, "INT13 out of space for %s table\n",
+		       acpi_name ( acpi->signature ) );
+		return -ENOSPC;
 	}
 
-	/* Reopen block device if necessary */
-	if ( sandev_needs_reopen ( sandev ) &&
-	     ( ( rc = sandev_reopen ( sandev ) ) != 0 ) )
-		return rc;
-	sanpath = sandev->active;
-	assert ( sanpath != NULL );
+	/* Install table */
+	installed = ( ( ( void * ) xbftab ) + xbftab_used );
+	memcpy ( installed, acpi, len );
+	xbft_address.segment = rm_ds;
+	xbft_address.offset = __from_data16 ( installed );
+
+	/* Fill in common parameters */
+	strncpy ( installed->oem_id, "FENSYS",
+		  sizeof ( installed->oem_id ) );
+	strncpy ( installed->oem_table_id, "iPXE",
+		  sizeof ( installed->oem_table_id ) );
+
+	/* Fix checksum */
+	acpi_fix_checksum ( installed );
+
+	/* Update used length */
+	xbftab_used = ( ( xbftab_used + len + XBFTAB_ALIGN - 1 ) &
+			~( XBFTAB_ALIGN - 1 ) );
+
+	DBGC ( acpi, "INT13 installed %s:\n",
+	       acpi_name ( installed->signature ) );
+	DBGC_HDA ( acpi, xbft_address, installed, len );
+	return 0;
+}
 
-	/* Clear table */
+/**
+ * Describe SAN devices for SAN-booted operating system
+ *
+ * @ret rc		Return status code
+ */
+static int int13_describe ( void ) {
+	int rc;
+
+	/* Clear tables */
 	memset ( &xbftab, 0, sizeof ( xbftab ) );
+	xbftab_used = 0;
 
-	/* Fill in common parameters */
-	strncpy ( xbftab.acpi.oem_id, "FENSYS",
-		  sizeof ( xbftab.acpi.oem_id ) );
-	strncpy ( xbftab.acpi.oem_table_id, "iPXE",
-		  sizeof ( xbftab.acpi.oem_table_id ) );
-
-	/* Fill in remaining parameters */
-	if ( ( rc = acpi_describe ( &sanpath->block, &xbftab.acpi,
-				    sizeof ( xbftab ) ) ) != 0 ) {
-		DBGC ( sandev, "INT13 drive %02x could not create ACPI "
-		       "description: %s\n", sandev->drive, strerror ( rc ) );
+	/* Install ACPI tables */
+	if ( ( rc = acpi_install ( int13_install ) ) != 0 ) {
+		DBG ( "INT13 could not install ACPI tables: %s\n",
+		      strerror ( rc ) );
 		return rc;
 	}
 
-	/* Fix up ACPI checksum */
-	acpi_fix_checksum ( &xbftab.acpi );
-	xbft_address.segment = rm_ds;
-	xbft_address.offset = __from_data16 ( &xbftab );
-	DBGC ( sandev, "INT13 drive %02x described using boot firmware "
-	       "table:\n", sandev->drive );
-	DBGC_HDA ( sandev, xbft_address, &xbftab,
-		   le32_to_cpu ( xbftab.acpi.length ) );
-
 	return 0;
 }