Re: [PATCH v5 4/7] xen: Put EFI machinery in place
From: Stefano Stabellini
Date: Mon Jun 16 2014 - 07:56:08 EST
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@xxxxxxxx>
> Signed-off-by: Tang Liang <liang.tang@xxxxxxxxxx>
> Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
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@xxxxxxxxxxx>
> + * Copyright (C) 1999-2002 Hewlett-Packard Co.
> + * David Mosberger-Tang <davidm@xxxxxxxxxx>
> + * Stephane Eranian <eranian@xxxxxxxxxx>
> + * Copyright (C) 2005-2008 Intel Co.
> + * Fenghua Yu <fenghua.yu@xxxxxxxxx>
> + * Bibo Mao <bibo.mao@xxxxxxxxx>
> + * Chandramouli Narayanan <mouli@xxxxxxxxxxxxxxx>
> + * Huang Ying <ying.huang@xxxxxxxxx>
> + * Copyright (C) 2011 Novell Co.
> + * Jan Beulich <JBeulich@xxxxxxxx>
> + * Copyright (C) 2011-2012 Oracle Co.
> + * Liang Tang <liang.tang@xxxxxxxxxx>
> + * 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.
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