diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/include/ipxe/vmbus.h | 14 | ||||
| -rw-r--r-- | src/interface/hyperv/vmbus.c | 86 |
2 files changed, 83 insertions, 17 deletions
diff --git a/src/include/ipxe/vmbus.h b/src/include/ipxe/vmbus.h index 1ea65edf..8725ee6a 100644 --- a/src/include/ipxe/vmbus.h +++ b/src/include/ipxe/vmbus.h @@ -42,8 +42,17 @@ union vmbus_version { }; } __attribute__ (( packed )); -/** Oldest known VMBus protocol version (Windows Server 2008) */ -#define VMBUS_VERSION_WS2008 ( ( 0 << 16 ) | ( 13 << 0 ) ) +/** Known VMBus protocol versions */ +enum vmbus_raw_version { + /** Windows Server 2008 */ + VMBUS_VERSION_WS2008 = ( ( 0 << 16 ) | ( 13 << 0 ) ), + /** Windows 7 */ + VMBUS_VERSION_WIN7 = ( ( 1 << 16 ) | ( 1 << 0 ) ), + /** Windows 8 */ + VMBUS_VERSION_WIN8 = ( ( 2 << 16 ) | ( 4 << 0 ) ), + /** Windows 8.1 */ + VMBUS_VERSION_WIN8_1 = ( ( 3 << 16 ) | ( 0 << 0 ) ), +}; /** Guest physical address range descriptor */ struct vmbus_gpa_range { @@ -82,6 +91,7 @@ enum vmbus_message_type { VMBUS_INITIATE_CONTACT = 14, VMBUS_VERSION_RESPONSE = 15, VMBUS_UNLOAD = 16, + VMBUS_UNLOAD_RESPONSE = 17, }; /** VMBus "offer channel" message */ diff --git a/src/interface/hyperv/vmbus.c b/src/interface/hyperv/vmbus.c index 79fa3e5e..9c18285d 100644 --- a/src/interface/hyperv/vmbus.c +++ b/src/interface/hyperv/vmbus.c @@ -38,13 +38,6 @@ FILE_LICENCE ( GPL2_OR_LATER ); #include <ipxe/hyperv.h> #include <ipxe/vmbus.h> -/** Chosen VMBus protocol version - * - * This is a policy decision. We use the oldest common version in - * order to avoid including any version-specific code. - */ -#define VMBUS_VERSION VMBUS_VERSION_WS2008 - /** VMBus initial GPADL ID * * This is an opaque value with no meaning. The Linux kernel uses @@ -122,9 +115,11 @@ static int vmbus_wait_for_message ( struct hv_hypervisor *hv ) { * Initiate contact * * @v hv Hyper-V hypervisor + * @v raw VMBus protocol (raw) version * @ret rc Return status code */ -static int vmbus_initiate_contact ( struct hv_hypervisor *hv ) { +static int vmbus_initiate_contact ( struct hv_hypervisor *hv, + unsigned int raw ) { struct vmbus *vmbus = hv->vmbus; const struct vmbus_version_response *version = &vmbus->message->version; struct vmbus_initiate_contact initiate; @@ -133,7 +128,7 @@ static int vmbus_initiate_contact ( struct hv_hypervisor *hv ) { /* Construct message */ memset ( &initiate, 0, sizeof ( initiate ) ); initiate.header.type = cpu_to_le32 ( VMBUS_INITIATE_CONTACT ); - initiate.version.raw = cpu_to_le32 ( VMBUS_VERSION ); + initiate.version.raw = cpu_to_le32 ( raw ); initiate.intr = virt_to_phys ( vmbus->intr ); initiate.monitor_in = virt_to_phys ( vmbus->monitor_in ); initiate.monitor_out = virt_to_phys ( vmbus->monitor_out ); @@ -158,7 +153,7 @@ static int vmbus_initiate_contact ( struct hv_hypervisor *hv ) { vmbus ); return -ENOTSUP; } - if ( version->version.raw != cpu_to_le32 ( VMBUS_VERSION ) ) { + if ( version->version.raw != cpu_to_le32 ( raw ) ) { DBGC ( vmbus, "VMBUS %p unexpected version %d.%d\n", vmbus, le16_to_cpu ( version->version.major ), le16_to_cpu ( version->version.minor ) ); @@ -178,8 +173,69 @@ static int vmbus_initiate_contact ( struct hv_hypervisor *hv ) { * @ret rc Return status code */ static int vmbus_unload ( struct hv_hypervisor *hv ) { + struct vmbus *vmbus = hv->vmbus; + const struct vmbus_message_header *header = &vmbus->message->header; + int rc; + + /* Post message */ + if ( ( rc = vmbus_post_empty_message ( hv, VMBUS_UNLOAD ) ) != 0 ) + return rc; + + /* Wait for response */ + if ( ( rc = vmbus_wait_for_message ( hv ) ) != 0 ) + return rc; + + /* Check response */ + if ( header->type != cpu_to_le32 ( VMBUS_UNLOAD_RESPONSE ) ) { + DBGC ( vmbus, "VMBUS %p unexpected unload response type %d\n", + vmbus, le32_to_cpu ( header->type ) ); + return -EPROTO; + } + + return 0; +} + +/** + * Negotiate protocol version + * + * @v hv Hyper-V hypervisor + * @ret rc Return status code + */ +static int vmbus_negotiate_version ( struct hv_hypervisor *hv ) { + int rc; - return vmbus_post_empty_message ( hv, VMBUS_UNLOAD ); + /* We require the ability to disconnect from and reconnect to + * VMBus; if we don't have this then there is no (viable) way + * for a loaded operating system to continue to use any VMBus + * devices. (There is also a small but non-zero risk that the + * host will continue to write to our interrupt and monitor + * pages, since the VMBUS_UNLOAD message in earlier versions + * is essentially a no-op.) + * + * This requires us to ensure that the host supports protocol + * version 3.0 (VMBUS_VERSION_WIN8_1). However, we can't + * actually _use_ protocol version 3.0, since doing so causes + * an iSCSI-booted Windows Server 2012 R2 VM to crash due to a + * NULL pointer dereference in vmbus.sys. + * + * To work around this problem, we first ensure that we can + * connect using protocol v3.0, then disconnect and reconnect + * using the oldest known protocol. + */ + + /* Initiate contact to check for required protocol support */ + if ( ( rc = vmbus_initiate_contact ( hv, VMBUS_VERSION_WIN8_1 ) ) != 0 ) + return rc; + + /* Terminate contact */ + if ( ( rc = vmbus_unload ( hv ) ) != 0 ) + return rc; + + /* Reinitiate contact using the oldest known protocol version */ + if ( ( rc = vmbus_initiate_contact ( hv, VMBUS_VERSION_WS2008 ) ) != 0 ) + return rc; + + return 0; } /** @@ -1232,9 +1288,9 @@ int vmbus_probe ( struct hv_hypervisor *hv, struct device *parent ) { /* Enable message interrupt */ hv_enable_sint ( hv, VMBUS_MESSAGE_SINT ); - /* Initiate contact */ - if ( ( rc = vmbus_initiate_contact ( hv ) ) != 0 ) - goto err_initiate_contact; + /* Negotiate protocol version */ + if ( ( rc = vmbus_negotiate_version ( hv ) ) != 0 ) + goto err_negotiate_version; /* Enumerate channels */ if ( ( rc = vmbus_probe_channels ( hv, parent ) ) != 0 ) @@ -1245,7 +1301,7 @@ int vmbus_probe ( struct hv_hypervisor *hv, struct device *parent ) { vmbus_remove_channels ( hv, parent ); err_probe_channels: vmbus_unload ( hv ); - err_initiate_contact: + err_negotiate_version: hv_disable_sint ( hv, VMBUS_MESSAGE_SINT ); hv_free_pages ( hv, vmbus->intr, vmbus->monitor_in, vmbus->monitor_out, NULL ); |