lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 16 Jun 2014 12:55:35 +0100
From:	Stefano Stabellini <stefano.stabellini@...citrix.com>
To:	Daniel Kiper <daniel.kiper@...cle.com>
CC:	<linux-efi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<x86@...nel.org>, <xen-devel@...ts.xenproject.org>,
	<andrew.cooper3@...rix.com>, <boris.ostrovsky@...cle.com>,
	<david.vrabel@...rix.com>, <eshelton@...ox.com>, <hpa@...or.com>,
	<ian.campbell@...rix.com>, <jbeulich@...e.com>, <jeremy@...p.org>,
	<konrad.wilk@...cle.com>, <matt.fleming@...el.com>,
	<mingo@...hat.com>, <mjg59@...f.ucam.org>,
	<stefano.stabellini@...citrix.com>, <tglx@...utronix.de>
Subject: Re: [PATCH v5 4/7] xen: Put EFI machinery in place

On Fri, 13 Jun 2014, Daniel Kiper wrote:
> This patch enables EFI usage under Xen dom0. Standard EFI Linux
> Kernel infrastructure cannot be used because it requires direct
> access to EFI data and code. However, in dom0 case it is not possible
> because above mentioned EFI stuff is fully owned and controlled
> by Xen hypervisor. In this case all calls from dom0 to EFI must
> be requested via special hypercall which in turn executes relevant
> EFI code in behalf of dom0.
> 
> When dom0 kernel boots it checks for EFI availability on a machine.
> If it is detected then artificial EFI system table is filled.
> Native EFI callas are replaced by functions which mimics them
> by calling relevant hypercall. Later pointer to EFI system table
> is passed to standard EFI machinery and it continues EFI subsystem
> initialization taking into account that there is no direct access
> to EFI boot services, runtime, tables, structures, etc. After that
> system runs as usual.
> 
> This patch is based on Jan Beulich and Tang Liang work.
> 
> v5 - suggestions/fixes:
>    - improve macro usage readability
>      (suggested by Andrew Cooper and David Vrabel),
>    - conditions cleanup
>      (suggested by David Vrabel),
>    - use -fshort-wchar option
>      (suggested by Jan Beulich),
>    - Kconfig rule cleanup
>      (suggested by Jan Beulich),
>    - forward port fixes from SUSE kernel
>      (suggested by Jan Beulich),
>    - improve commit message
>      (suggested by David Vrabel).
> 
> v4 - suggestions/fixes:
>    - "just populate an efi_system_table_t object"
>      (suggested by Matt Fleming).
> 
> Signed-off-by: Jan Beulich <jbeulich@...e.com>
> Signed-off-by: Tang Liang <liang.tang@...cle.com>
> Signed-off-by: Daniel Kiper <daniel.kiper@...cle.com>

Sorry for commenting on your patches so late in the review cycle.


>  arch/x86/xen/enlighten.c |   24 +++
>  drivers/xen/Kconfig      |    4 +
>  drivers/xen/Makefile     |    3 +
>  drivers/xen/efi.c        |  374 ++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 405 insertions(+)
>  create mode 100644 drivers/xen/efi.c
> 
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index f17b292..5dad11c 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -32,6 +32,7 @@
>  #include <linux/gfp.h>
>  #include <linux/memblock.h>
>  #include <linux/edd.h>
> +#include <linux/efi.h>
>  
>  #include <xen/xen.h>
>  #include <xen/events.h>
> @@ -150,6 +151,15 @@ struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
>   */
>  static int have_vcpu_info_placement = 1;
>  
> +#ifdef CONFIG_XEN_EFI
> +extern efi_system_table_t __init *xen_efi_probe(void);
> +#else
> +static efi_system_table_t __init *xen_efi_probe(void)
> +{
> +	return NULL;
> +}
> +#endif
> +
>  struct tls_descs {
>  	struct desc_struct desc[3];
>  };
> @@ -1520,6 +1530,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
>  {
>  	struct physdev_set_iopl set_iopl;
>  	int rc;
> +	efi_system_table_t *efi_systab_xen;
>  
>  	if (!xen_start_info)
>  		return;
> @@ -1715,6 +1726,19 @@ asmlinkage __visible void __init xen_start_kernel(void)
>  
>  	xen_setup_runstate_info(0);
>  
> +	efi_systab_xen = xen_efi_probe();
> +
> +	if (efi_systab_xen) {
> +		strncpy((char *)&boot_params.efi_info.efi_loader_signature, "Xen",
> +				sizeof(boot_params.efi_info.efi_loader_signature));
> +		boot_params.efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
> +		boot_params.efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
> +
> +		set_bit(EFI_BOOT, &efi.flags);
> +		set_bit(EFI_NO_DIRECT, &efi.flags);
> +		set_bit(EFI_64BIT, &efi.flags);
> +	}
> +
>  	/* Start the world */
>  #ifdef CONFIG_X86_32
>  	i386_start_kernel();
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 38fb36e..8bc0183 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -240,4 +240,8 @@ config XEN_MCE_LOG
>  config XEN_HAVE_PVMMU
>         bool
>  
> +config XEN_EFI
> +	def_bool y
> +	depends on X86_64 && EFI
> +
>  endmenu
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index 45e00af..84044b5 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -9,6 +9,8 @@ obj-y	+= xenbus/
>  nostackp := $(call cc-option, -fno-stack-protector)
>  CFLAGS_features.o			:= $(nostackp)
>  
> +CFLAGS_efi.o				+= -fshort-wchar
> +
>  dom0-$(CONFIG_PCI) += pci.o
>  dom0-$(CONFIG_USB_SUPPORT) += dbgp.o
>  dom0-$(CONFIG_ACPI) += acpi.o $(xen-pad-y)
> @@ -33,6 +35,7 @@ obj-$(CONFIG_XEN_STUB)			+= xen-stub.o
>  obj-$(CONFIG_XEN_ACPI_HOTPLUG_MEMORY)	+= xen-acpi-memhotplug.o
>  obj-$(CONFIG_XEN_ACPI_HOTPLUG_CPU)	+= xen-acpi-cpuhotplug.o
>  obj-$(CONFIG_XEN_ACPI_PROCESSOR)	+= xen-acpi-processor.o
> +obj-$(CONFIG_XEN_EFI)			+= efi.o
>  xen-evtchn-y				:= evtchn.o
>  xen-gntdev-y				:= gntdev.o
>  xen-gntalloc-y				:= gntalloc.o
> diff --git a/drivers/xen/efi.c b/drivers/xen/efi.c
> new file mode 100644
> index 0000000..e3d6618
> --- /dev/null
> +++ b/drivers/xen/efi.c
> @@ -0,0 +1,374 @@
> +/*
> + * EFI support for Xen.
> + *
> + * Copyright (C) 1999 VA Linux Systems
> + * Copyright (C) 1999 Walt Drummond <drummond@...inux.com>
> + * Copyright (C) 1999-2002 Hewlett-Packard Co.
> + *	David Mosberger-Tang <davidm@....hp.com>
> + *	Stephane Eranian <eranian@....hp.com>
> + * Copyright (C) 2005-2008 Intel Co.
> + *	Fenghua Yu <fenghua.yu@...el.com>
> + *	Bibo Mao <bibo.mao@...el.com>
> + *	Chandramouli Narayanan <mouli@...ux.intel.com>
> + *	Huang Ying <ying.huang@...el.com>
> + * Copyright (C) 2011 Novell Co.
> + *	Jan Beulich <JBeulich@...e.com>
> + * Copyright (C) 2011-2012 Oracle Co.
> + *	Liang Tang <liang.tang@...cle.com>
> + * Copyright (c) 2014 Oracle Corporation, Daniel Kiper
> + */
> +
> +#include <linux/bug.h>
> +#include <linux/efi.h>
> +#include <linux/init.h>
> +#include <linux/string.h>
> +
> +#include <xen/interface/xen.h>
> +#include <xen/interface/platform.h>
> +
> +#include <asm/xen/hypercall.h>
> +
> +#define INIT_EFI_OP(name) \
> +	{.cmd = XENPF_efi_runtime_call, \
> +	 .u.efi_runtime_call.function = XEN_EFI_##name, \
> +	 .u.efi_runtime_call.misc = 0}
> +
> +#define efi_data(op)	(op.u.efi_runtime_call)
> +
> +static efi_status_t xen_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(get_time);
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	if (tm) {
> +		BUILD_BUG_ON(sizeof(*tm) != sizeof(efi_data(op).u.get_time.time));
> +		memcpy(tm, &efi_data(op).u.get_time.time, sizeof(*tm));
> +	}
> +
> +	if (tc) {
> +		tc->resolution = efi_data(op).u.get_time.resolution;
> +		tc->accuracy = efi_data(op).u.get_time.accuracy;
> +		tc->sets_to_zero = !!(efi_data(op).misc &
> +				      XEN_EFI_GET_TIME_SET_CLEARS_NS);
> +	}
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_set_time(efi_time_t *tm)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(set_time);
> +
> +	BUILD_BUG_ON(sizeof(*tm) != sizeof(efi_data(op).u.set_time));
> +	memcpy(&efi_data(op).u.set_time, tm, sizeof(*tm));
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_get_wakeup_time(efi_bool_t *enabled,
> +					    efi_bool_t *pending,
> +					    efi_time_t *tm)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(get_wakeup_time);
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	if (tm) {
> +		BUILD_BUG_ON(sizeof(*tm) != sizeof(efi_data(op).u.get_wakeup_time));
> +		memcpy(tm, &efi_data(op).u.get_wakeup_time, sizeof(*tm));
> +	}
> +
> +	if (enabled)
> +		*enabled = !!(efi_data(op).misc & XEN_EFI_GET_WAKEUP_TIME_ENABLED);
> +
> +	if (pending)
> +		*pending = !!(efi_data(op).misc & XEN_EFI_GET_WAKEUP_TIME_PENDING);
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(set_wakeup_time);
> +
> +	BUILD_BUG_ON(sizeof(*tm) != sizeof(efi_data(op).u.set_wakeup_time));
> +	if (enabled)
> +		efi_data(op).misc = XEN_EFI_SET_WAKEUP_TIME_ENABLE;
> +	if (tm)
> +		memcpy(&efi_data(op).u.set_wakeup_time, tm, sizeof(*tm));
> +	else
> +		efi_data(op).misc |= XEN_EFI_SET_WAKEUP_TIME_ENABLE_ONLY;
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_get_variable(efi_char16_t *name,
> +					 efi_guid_t *vendor,
> +					 u32 *attr,
> +					 unsigned long *data_size,
> +					 void *data)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(get_variable);
> +
> +	set_xen_guest_handle(efi_data(op).u.get_variable.name, name);
> +	BUILD_BUG_ON(sizeof(*vendor) !=
> +		     sizeof(efi_data(op).u.get_variable.vendor_guid));
> +	memcpy(&efi_data(op).u.get_variable.vendor_guid, vendor, sizeof(*vendor));
> +	efi_data(op).u.get_variable.size = *data_size;
> +	set_xen_guest_handle(efi_data(op).u.get_variable.data, data);
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	*data_size = efi_data(op).u.get_variable.size;
> +	if (attr)
> +		*attr = efi_data(op).misc;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_get_next_variable(unsigned long *name_size,
> +					      efi_char16_t *name,
> +					      efi_guid_t *vendor)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(get_next_variable_name);
> +
> +	efi_data(op).u.get_next_variable_name.size = *name_size;
> +	set_xen_guest_handle(efi_data(op).u.get_next_variable_name.name, name);
> +	BUILD_BUG_ON(sizeof(*vendor) !=
> +		     sizeof(efi_data(op).u.get_next_variable_name.vendor_guid));
> +	memcpy(&efi_data(op).u.get_next_variable_name.vendor_guid, vendor,
> +	       sizeof(*vendor));
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	*name_size = efi_data(op).u.get_next_variable_name.size;
> +	memcpy(vendor, &efi_data(op).u.get_next_variable_name.vendor_guid,
> +	       sizeof(*vendor));
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_set_variable(efi_char16_t *name,
> +					 efi_guid_t *vendor,
> +					 u32 attr,
> +					 unsigned long data_size,
> +					 void *data)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(set_variable);
> +
> +	set_xen_guest_handle(efi_data(op).u.set_variable.name, name);
> +	efi_data(op).misc = attr;
> +	BUILD_BUG_ON(sizeof(*vendor) !=
> +		     sizeof(efi_data(op).u.set_variable.vendor_guid));
> +	memcpy(&efi_data(op).u.set_variable.vendor_guid, vendor, sizeof(*vendor));
> +	efi_data(op).u.set_variable.size = data_size;
> +	set_xen_guest_handle(efi_data(op).u.set_variable.data, data);
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_query_variable_info(u32 attr,
> +						u64 *storage_space,
> +						u64 *remaining_space,
> +						u64 *max_variable_size)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(query_variable_info);
> +
> +	if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
> +		return EFI_UNSUPPORTED;
> +
> +	efi_data(op).u.query_variable_info.attr = attr;
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	*storage_space = efi_data(op).u.query_variable_info.max_store_size;
> +	*remaining_space = efi_data(op).u.query_variable_info.remain_store_size;
> +	*max_variable_size = efi_data(op).u.query_variable_info.max_size;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_get_next_high_mono_count(u32 *count)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(get_next_high_monotonic_count);
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	*count = efi_data(op).misc;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_update_capsule(efi_capsule_header_t **capsules,
> +					   unsigned long count,
> +					   unsigned long sg_list)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(update_capsule);
> +
> +	if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
> +		return EFI_UNSUPPORTED;
> +
> +	set_xen_guest_handle(efi_data(op).u.update_capsule.capsule_header_array,
> +			     capsules);
> +	efi_data(op).u.update_capsule.capsule_count = count;
> +	efi_data(op).u.update_capsule.sg_list = sg_list;
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_status_t xen_efi_query_capsule_caps(efi_capsule_header_t **capsules,
> +					       unsigned long count,
> +					       u64 *max_size,
> +					       int *reset_type)
> +{
> +	struct xen_platform_op op = INIT_EFI_OP(query_capsule_capabilities);
> +
> +	if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
> +		return EFI_UNSUPPORTED;
> +
> +	set_xen_guest_handle(efi_data(op).u.query_capsule_capabilities.capsule_header_array,
> +					capsules);
> +	efi_data(op).u.query_capsule_capabilities.capsule_count = count;
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		return EFI_UNSUPPORTED;
> +
> +	*max_size = efi_data(op).u.query_capsule_capabilities.max_capsule_size;
> +	*reset_type = efi_data(op).u.query_capsule_capabilities.reset_type;
> +
> +	return efi_data(op).status;
> +}
> +
> +static efi_char16_t vendor[100] __initdata;
> +
> +static efi_system_table_t efi_systab_xen __initdata = {
> +	.hdr = {
> +		.signature	= EFI_SYSTEM_TABLE_SIGNATURE,
> +		.revision	= 0, /* Initialized later. */
> +		.headersize	= 0, /* Ignored by Linux Kernel. */
> +		.crc32		= 0, /* Ignored by Linux Kernel. */
> +		.reserved	= 0
> +	},
> +	.fw_vendor	= EFI_INVALID_TABLE_ADDR, /* Initialized later. */
> +	.fw_revision	= 0,			  /* Initialized later. */
> +	.con_in_handle	= EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
> +	.con_in		= EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
> +	.con_out_handle	= EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
> +	.con_out	= EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
> +	.stderr_handle	= EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
> +	.stderr		= EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */
> +	.runtime	= (efi_runtime_services_t *)EFI_INVALID_TABLE_ADDR,
> +						  /* Not used under Xen. */
> +	.boottime	= (efi_boot_services_t *)EFI_INVALID_TABLE_ADDR,
> +						  /* Not used under Xen. */
> +	.nr_tables	= 0,			  /* Initialized later. */
> +	.tables		= EFI_INVALID_TABLE_ADDR  /* Initialized later. */
> +};
> +
> +static const struct efi efi_xen __initconst = {
> +	.systab                   = NULL, /* Initialized later. */
> +	.runtime_version	  = 0,    /* Initialized later. */
> +	.mps                      = EFI_INVALID_TABLE_ADDR,
> +	.acpi                     = EFI_INVALID_TABLE_ADDR,
> +	.acpi20                   = EFI_INVALID_TABLE_ADDR,
> +	.smbios                   = EFI_INVALID_TABLE_ADDR,
> +	.sal_systab               = EFI_INVALID_TABLE_ADDR,
> +	.boot_info                = EFI_INVALID_TABLE_ADDR,
> +	.hcdp                     = EFI_INVALID_TABLE_ADDR,
> +	.uga                      = EFI_INVALID_TABLE_ADDR,
> +	.uv_systab                = EFI_INVALID_TABLE_ADDR,
> +	.fw_vendor                = EFI_INVALID_TABLE_ADDR,
> +	.runtime                  = EFI_INVALID_TABLE_ADDR,
> +	.config_table             = EFI_INVALID_TABLE_ADDR,
> +	.get_time                 = xen_efi_get_time,
> +	.set_time                 = xen_efi_set_time,
> +	.get_wakeup_time          = xen_efi_get_wakeup_time,
> +	.set_wakeup_time          = xen_efi_set_wakeup_time,
> +	.get_variable             = xen_efi_get_variable,
> +	.get_next_variable        = xen_efi_get_next_variable,
> +	.set_variable             = xen_efi_set_variable,
> +	.query_variable_info      = xen_efi_query_variable_info,
> +	.update_capsule           = xen_efi_update_capsule,
> +	.query_capsule_caps       = xen_efi_query_capsule_caps,
> +	.get_next_high_mono_count = xen_efi_get_next_high_mono_count,
> +	.reset_system             = NULL, /* Functionality provided by Xen. */
> +	.set_virtual_address_map  = NULL, /* Not used under Xen. */
> +	.memmap                   = NULL, /* Not used under Xen. */
> +	.flags			  = 0     /* Initialized later. */
> +};
> +
> +efi_system_table_t __init *xen_efi_probe(void)
> +{
> +	struct xen_platform_op op = {
> +		.cmd = XENPF_firmware_info,
> +		.u.firmware_info = {
> +			.type = XEN_FW_EFI_INFO,
> +			.index = XEN_FW_EFI_CONFIG_TABLE
> +		}
> +	};
> +	union xenpf_efi_info *info = &op.u.firmware_info.u.efi_info;
> +
> +	if (!xen_initial_domain() || HYPERVISOR_dom0_op(&op) < 0)
> +		return NULL;
> +
> +	/* Here we know that Xen runs on EFI platform. */
> +
> +	efi = efi_xen;
> +
> +	op.cmd = XENPF_firmware_info;
> +	op.u.firmware_info.type = XEN_FW_EFI_INFO;
> +	op.u.firmware_info.index = XEN_FW_EFI_VENDOR;
> +	info->vendor.bufsz = sizeof(vendor);
> +	set_xen_guest_handle(info->vendor.name, vendor);
> +
> +	if (HYPERVISOR_dom0_op(&op) == 0) {
> +		efi_systab_xen.fw_vendor = __pa_symbol(vendor);
> +		efi_systab_xen.fw_revision = info->vendor.revision;
> +	} else
> +		efi_systab_xen.fw_vendor = __pa_symbol(L"UNKNOWN");
> +
> +	op.cmd = XENPF_firmware_info;
> +	op.u.firmware_info.type = XEN_FW_EFI_INFO;
> +	op.u.firmware_info.index = XEN_FW_EFI_VERSION;
> +
> +	if (HYPERVISOR_dom0_op(&op) == 0)
> +		efi_systab_xen.hdr.revision = info->version;
> +
> +	op.cmd = XENPF_firmware_info;
> +	op.u.firmware_info.type = XEN_FW_EFI_INFO;
> +	op.u.firmware_info.index = XEN_FW_EFI_RT_VERSION;
> +
> +	if (HYPERVISOR_dom0_op(&op) == 0)
> +		efi.runtime_version = info->version;
> +
> +	op.cmd = XENPF_firmware_info;
> +	op.u.firmware_info.type = XEN_FW_EFI_INFO;
> +	op.u.firmware_info.index = XEN_FW_EFI_CONFIG_TABLE;
> +
> +	if (HYPERVISOR_dom0_op(&op) < 0)
> +		BUG();

Is it really worth of a BUG()? Can't we just print a warning and return
NULL? We could still boot without EFI support.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists