| Message ID | 20211020061408.3447533-3-dovmurik@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Allow guest access to EFI confidential computing secret area | expand |
On Wed, Oct 20, 2021 at 06:14:07AM +0000, Dov Murik wrote: > When efi-stub copies an EFI-provided confidential computing (coco) > secret area, reserve that memory block for future use within the kernel. > > Signed-off-by: Dov Murik <dovmurik@linux.ibm.com> > --- > arch/x86/platform/efi/efi.c | 3 +++ > drivers/firmware/efi/Makefile | 1 + > drivers/firmware/efi/coco.c | 41 +++++++++++++++++++++++++++++++++++ > drivers/firmware/efi/efi.c | 8 +++++++ > include/linux/efi.h | 10 +++++++++ > 5 files changed, 63 insertions(+) > create mode 100644 drivers/firmware/efi/coco.c > > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c > index 147c30a81f15..1591d67e0bcd 100644 > --- a/arch/x86/platform/efi/efi.c > +++ b/arch/x86/platform/efi/efi.c > @@ -93,6 +93,9 @@ static const unsigned long * const efi_tables[] = { > #ifdef CONFIG_LOAD_UEFI_KEYS > &efi.mokvar_table, > #endif > +#ifdef CONFIG_EFI_COCO_SECRET > + &efi.coco_secret, > +#endif > }; > > u64 efi_setup; /* efi setup_data physical address */ > diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile > index c02ff25dd477..49c4a8c0bfc4 100644 > --- a/drivers/firmware/efi/Makefile > +++ b/drivers/firmware/efi/Makefile > @@ -32,6 +32,7 @@ obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o > obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o > obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o > obj-$(CONFIG_LOAD_UEFI_KEYS) += mokvar-table.o > +obj-$(CONFIG_EFI_COCO_SECRET) += coco.o > > fake_map-y += fake_mem.o > fake_map-$(CONFIG_X86) += x86_fake_mem.o > diff --git a/drivers/firmware/efi/coco.c b/drivers/firmware/efi/coco.c > new file mode 100644 > index 000000000000..42f477d6188c > --- /dev/null > +++ b/drivers/firmware/efi/coco.c > @@ -0,0 +1,41 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Confidential computing (coco) secret area handling > + * > + * Copyright (C) 2021 IBM Corporation > + * Author: Dov Murik <dovmurik@linux.ibm.com> > + */ > + > +#define pr_fmt(fmt) "efi: " fmt > + > +#include <linux/efi.h> > +#include <linux/init.h> > +#include <linux/memblock.h> > +#include <asm/early_ioremap.h> > + > +/* > + * Reserve the confidential computing secret area memory > + */ > +int __init efi_coco_secret_area_reserve(void) > +{ > + struct linux_efi_coco_secret_area *secret_area; > + unsigned long secret_area_size; > + > + if (efi.coco_secret == EFI_INVALID_TABLE_ADDR) > + return 0; > + > + secret_area = early_memremap(efi.coco_secret, sizeof(*secret_area)); > + if (!secret_area) { > + pr_err("Failed to map confidential computing secret area\n"); > + efi.coco_secret = EFI_INVALID_TABLE_ADDR; > + return -ENOMEM; > + } > + > + secret_area_size = sizeof(*secret_area) + secret_area->size; > + memblock_reserve(efi.coco_secret, secret_area_size); > + > + pr_info("Reserved memory of EFI-provided confidential computing secret area"); When kernel code works properly, it is quiet. Why do you need to print this out at every boot? > + > + early_memunmap(secret_area, sizeof(*secret_area)); > + return 0; > +} And again, when is this memory freed when shutting down? thanks, greg k-h
On 20/10/2021 9:40, Greg KH wrote: > On Wed, Oct 20, 2021 at 06:14:07AM +0000, Dov Murik wrote: >> When efi-stub copies an EFI-provided confidential computing (coco) >> secret area, reserve that memory block for future use within the kernel. >> >> Signed-off-by: Dov Murik <dovmurik@linux.ibm.com> >> --- >> arch/x86/platform/efi/efi.c | 3 +++ >> drivers/firmware/efi/Makefile | 1 + >> drivers/firmware/efi/coco.c | 41 +++++++++++++++++++++++++++++++++++ >> drivers/firmware/efi/efi.c | 8 +++++++ >> include/linux/efi.h | 10 +++++++++ >> 5 files changed, 63 insertions(+) >> create mode 100644 drivers/firmware/efi/coco.c >> >> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c >> index 147c30a81f15..1591d67e0bcd 100644 >> --- a/arch/x86/platform/efi/efi.c >> +++ b/arch/x86/platform/efi/efi.c >> @@ -93,6 +93,9 @@ static const unsigned long * const efi_tables[] = { >> #ifdef CONFIG_LOAD_UEFI_KEYS >> &efi.mokvar_table, >> #endif >> +#ifdef CONFIG_EFI_COCO_SECRET >> + &efi.coco_secret, >> +#endif >> }; >> >> u64 efi_setup; /* efi setup_data physical address */ >> diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile >> index c02ff25dd477..49c4a8c0bfc4 100644 >> --- a/drivers/firmware/efi/Makefile >> +++ b/drivers/firmware/efi/Makefile >> @@ -32,6 +32,7 @@ obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o >> obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o >> obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o >> obj-$(CONFIG_LOAD_UEFI_KEYS) += mokvar-table.o >> +obj-$(CONFIG_EFI_COCO_SECRET) += coco.o >> >> fake_map-y += fake_mem.o >> fake_map-$(CONFIG_X86) += x86_fake_mem.o >> diff --git a/drivers/firmware/efi/coco.c b/drivers/firmware/efi/coco.c >> new file mode 100644 >> index 000000000000..42f477d6188c >> --- /dev/null >> +++ b/drivers/firmware/efi/coco.c >> @@ -0,0 +1,41 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Confidential computing (coco) secret area handling >> + * >> + * Copyright (C) 2021 IBM Corporation >> + * Author: Dov Murik <dovmurik@linux.ibm.com> >> + */ >> + >> +#define pr_fmt(fmt) "efi: " fmt >> + >> +#include <linux/efi.h> >> +#include <linux/init.h> >> +#include <linux/memblock.h> >> +#include <asm/early_ioremap.h> >> + >> +/* >> + * Reserve the confidential computing secret area memory >> + */ >> +int __init efi_coco_secret_area_reserve(void) >> +{ >> + struct linux_efi_coco_secret_area *secret_area; >> + unsigned long secret_area_size; >> + >> + if (efi.coco_secret == EFI_INVALID_TABLE_ADDR) >> + return 0; >> + >> + secret_area = early_memremap(efi.coco_secret, sizeof(*secret_area)); >> + if (!secret_area) { >> + pr_err("Failed to map confidential computing secret area\n"); >> + efi.coco_secret = EFI_INVALID_TABLE_ADDR; >> + return -ENOMEM; >> + } >> + >> + secret_area_size = sizeof(*secret_area) + secret_area->size; >> + memblock_reserve(efi.coco_secret, secret_area_size); >> + >> + pr_info("Reserved memory of EFI-provided confidential computing secret area"); > > When kernel code works properly, it is quiet. Why do you need to print > this out at every boot? > My kernel is not so quiet at the info loglevel; specifically from efi I see these prints (third log line added by this patch): [ 0.000000] efi: EFI v2.70 by EDK II [ 0.000000] efi: SMBIOS=0x7f541000 ACPI=0x7f77e000 ACPI 2.0=0x7f77e014 MEMATTR=0x7ea0c018 CocoSecret=0x7ea0b018 [ 0.000000] efi: Reserved memory of EFI-provided confidential computing secret area This print is useful to understand that both OVMF (EFI) and kernel support the confidential computing secret area. >> + >> + early_memunmap(secret_area, sizeof(*secret_area)); >> + return 0; >> +} > > And again, when is this memory freed when shutting down? > It is currently not freed. I tried to look for such memory freeing of other EFI-provided memory areas (such as efi.tpm_final_log) and couldn't find them. Can you please share pointers/examples of how to do that? Thanks, -Dov
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 147c30a81f15..1591d67e0bcd 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -93,6 +93,9 @@ static const unsigned long * const efi_tables[] = { #ifdef CONFIG_LOAD_UEFI_KEYS &efi.mokvar_table, #endif +#ifdef CONFIG_EFI_COCO_SECRET + &efi.coco_secret, +#endif }; u64 efi_setup; /* efi setup_data physical address */ diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index c02ff25dd477..49c4a8c0bfc4 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -32,6 +32,7 @@ obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o obj-$(CONFIG_LOAD_UEFI_KEYS) += mokvar-table.o +obj-$(CONFIG_EFI_COCO_SECRET) += coco.o fake_map-y += fake_mem.o fake_map-$(CONFIG_X86) += x86_fake_mem.o diff --git a/drivers/firmware/efi/coco.c b/drivers/firmware/efi/coco.c new file mode 100644 index 000000000000..42f477d6188c --- /dev/null +++ b/drivers/firmware/efi/coco.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Confidential computing (coco) secret area handling + * + * Copyright (C) 2021 IBM Corporation + * Author: Dov Murik <dovmurik@linux.ibm.com> + */ + +#define pr_fmt(fmt) "efi: " fmt + +#include <linux/efi.h> +#include <linux/init.h> +#include <linux/memblock.h> +#include <asm/early_ioremap.h> + +/* + * Reserve the confidential computing secret area memory + */ +int __init efi_coco_secret_area_reserve(void) +{ + struct linux_efi_coco_secret_area *secret_area; + unsigned long secret_area_size; + + if (efi.coco_secret == EFI_INVALID_TABLE_ADDR) + return 0; + + secret_area = early_memremap(efi.coco_secret, sizeof(*secret_area)); + if (!secret_area) { + pr_err("Failed to map confidential computing secret area\n"); + efi.coco_secret = EFI_INVALID_TABLE_ADDR; + return -ENOMEM; + } + + secret_area_size = sizeof(*secret_area) + secret_area->size; + memblock_reserve(efi.coco_secret, secret_area_size); + + pr_info("Reserved memory of EFI-provided confidential computing secret area"); + + early_memunmap(secret_area, sizeof(*secret_area)); + return 0; +} diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 847f33ffc4ae..31bdae2afc47 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -46,6 +46,9 @@ struct efi __read_mostly efi = { #ifdef CONFIG_LOAD_UEFI_KEYS .mokvar_table = EFI_INVALID_TABLE_ADDR, #endif +#ifdef CONFIG_EFI_COCO_SECRET + .coco_secret = EFI_INVALID_TABLE_ADDR, +#endif }; EXPORT_SYMBOL(efi); @@ -525,6 +528,9 @@ static const efi_config_table_type_t common_tables[] __initconst = { #endif #ifdef CONFIG_LOAD_UEFI_KEYS {LINUX_EFI_MOK_VARIABLE_TABLE_GUID, &efi.mokvar_table, "MOKvar" }, +#endif +#ifdef CONFIG_EFI_COCO_SECRET + {LINUX_EFI_COCO_SECRET_AREA_GUID, &efi.coco_secret, "CocoSecret" }, #endif {}, }; @@ -613,6 +619,8 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables, efi_tpm_eventlog_init(); + efi_coco_secret_area_reserve(); + if (mem_reserve != EFI_INVALID_TABLE_ADDR) { unsigned long prsv = mem_reserve; diff --git a/include/linux/efi.h b/include/linux/efi.h index 9021dd521302..6e57dd083e25 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -550,6 +550,7 @@ extern struct efi { unsigned long tpm_log; /* TPM2 Event Log table */ unsigned long tpm_final_log; /* TPM2 Final Events Log table */ unsigned long mokvar_table; /* MOK variable config table */ + unsigned long coco_secret; /* Confidential computing secret table */ efi_get_time_t *get_time; efi_set_time_t *set_time; @@ -1288,4 +1289,13 @@ struct linux_efi_coco_secret_area { u8 area[]; }; +#ifdef CONFIG_EFI_COCO_SECRET +extern int efi_coco_secret_area_reserve(void); +#else +static inline int efi_coco_secret_area_reserve(void) +{ + return 0; +} +#endif + #endif /* _LINUX_EFI_H */
When efi-stub copies an EFI-provided confidential computing (coco) secret area, reserve that memory block for future use within the kernel. Signed-off-by: Dov Murik <dovmurik@linux.ibm.com> --- arch/x86/platform/efi/efi.c | 3 +++ drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/coco.c | 41 +++++++++++++++++++++++++++++++++++ drivers/firmware/efi/efi.c | 8 +++++++ include/linux/efi.h | 10 +++++++++ 5 files changed, 63 insertions(+) create mode 100644 drivers/firmware/efi/coco.c