| Message ID | 20240214221847.2066632-16-ross.philipson@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: Trenchboot secure dynamic launch Linux kernel support | expand |
On Wed, 14 Feb 2024 at 23:32, Ross Philipson <ross.philipson@oracle.com> wrote: > > This support allows the DRTM launch to be initiated after an EFI stub > launch of the Linux kernel is done. This is accomplished by providing > a handler to jump to when a Secure Launch is in progress. This has to be > called after the EFI stub does Exit Boot Services. > > Signed-off-by: Ross Philipson <ross.philipson@oracle.com> > --- > drivers/firmware/efi/libstub/x86-stub.c | 55 +++++++++++++++++++++++++ > 1 file changed, 55 insertions(+) > > diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c > index 0d510c9a06a4..4df2cf539194 100644 > --- a/drivers/firmware/efi/libstub/x86-stub.c > +++ b/drivers/firmware/efi/libstub/x86-stub.c > @@ -9,6 +9,7 @@ > #include <linux/efi.h> > #include <linux/pci.h> > #include <linux/stddef.h> > +#include <linux/slr_table.h> > > #include <asm/efi.h> > #include <asm/e820/types.h> > @@ -810,6 +811,57 @@ static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry) > return EFI_SUCCESS; > } > > +static void efi_secure_launch(struct boot_params *boot_params) > +{ > + struct slr_entry_uefi_config *uefi_config; > + struct slr_uefi_cfg_entry *uefi_entry; > + struct slr_entry_dl_info *dlinfo; > + efi_guid_t guid = SLR_TABLE_GUID; > + struct slr_table *slrt; > + u64 memmap_hi; > + void *table; > + u8 buf[64] = {0}; > + If you add a flex array to slr_entry_uefi_config as I suggested in response to the other patch, we could simplify this substantially static struct slr_entry_uefi_config cfg = { .hdr.tag = SLR_ENTRY_UEFI_CONFIG, .hdr.size = sizeof(cfg), .revision = SLR_UEFI_CONFIG_REVISION, .nr_entries = 1, .entries[0] = { .pcr = 18, .evt_info = "Measured UEFI memory map", }, }; cfg.entries[0].cfg = boot_params->efi_info.efi_memmap | (u64)boot_params->efi_info.efi_memmap_hi << 32; cfg.entries[0].size = boot_params->efi_info.efi_memmap_size; > + table = get_efi_config_table(guid); > + > + /* > + * The presence of this table indicated a Secure Launch > + * is being requested. > + */ > + if (!table) > + return; > + > + slrt = (struct slr_table *)table; > + > + if (slrt->magic != SLR_TABLE_MAGIC) > + return; > + slrt = (struct slr_table *)get_efi_config_table(guid); if (!slrt || slrt->magic != SLR_TABLE_MAGIC) return; > + /* Add config information to measure the UEFI memory map */ > + uefi_config = (struct slr_entry_uefi_config *)buf; > + uefi_config->hdr.tag = SLR_ENTRY_UEFI_CONFIG; > + uefi_config->hdr.size = sizeof(*uefi_config) + sizeof(*uefi_entry); > + uefi_config->revision = SLR_UEFI_CONFIG_REVISION; > + uefi_config->nr_entries = 1; > + uefi_entry = (struct slr_uefi_cfg_entry *)(buf + sizeof(*uefi_config)); > + uefi_entry->pcr = 18; > + uefi_entry->cfg = boot_params->efi_info.efi_memmap; > + memmap_hi = boot_params->efi_info.efi_memmap_hi; > + uefi_entry->cfg |= memmap_hi << 32; > + uefi_entry->size = boot_params->efi_info.efi_memmap_size; > + memcpy(&uefi_entry->evt_info[0], "Measured UEFI memory map", > + strlen("Measured UEFI memory map")); > + Drop all of this > + if (slr_add_entry(slrt, (struct slr_entry_hdr *)uefi_config)) if (slr_add_entry(slrt, &uefi_config.hdr)) > + return; > + > + /* Jump through DL stub to initiate Secure Launch */ > + dlinfo = (struct slr_entry_dl_info *) > + slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); > + > + asm volatile ("jmp *%%rax" > + : : "a" (dlinfo->dl_handler), "D" (&dlinfo->bl_context)); Fix the prototype and just do dlinfo->dl_handler(&dlinfo->bl_context); unreachable(); So in summary, this becomes static void efi_secure_launch(struct boot_params *boot_params) { static struct slr_entry_uefi_config cfg = { .hdr.tag = SLR_ENTRY_UEFI_CONFIG, .hdr.size = sizeof(cfg), .revision = SLR_UEFI_CONFIG_REVISION, .nr_entries = 1, .entries[0] = { .pcr = 18, .evt_info = "Measured UEFI memory map", }, }; struct slr_entry_dl_info *dlinfo; efi_guid_t guid = SLR_TABLE_GUID; struct slr_table *slrt; /* * The presence of this table indicated a Secure Launch * is being requested. */ slrt = (struct slr_table *)get_efi_config_table(guid); if (!slrt || slrt->magic != SLR_TABLE_MAGIC) return; cfg.entries[0].cfg = boot_params->efi_info.efi_memmap | (u64)boot_params->efi_info.efi_memmap_hi << 32; cfg.entries[0].size = boot_params->efi_info.efi_memmap_size; if (slr_add_entry(slrt, &cfg.hdr)) return; /* Jump through DL stub to initiate Secure Launch */ dlinfo = (struct slr_entry_dl_info *) slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); dlinfo->dl_handler(&dlinfo->bl_context); unreachable(); } > +} > + > static void __noreturn enter_kernel(unsigned long kernel_addr, > struct boot_params *boot_params) > { > @@ -934,6 +986,9 @@ void __noreturn efi_stub_entry(efi_handle_t handle, > goto fail; > } > > + /* If a Secure Launch is in progress, this never returns */ if (IS_ENABLED(CONFIG_SECURE_LAUNCH)) > + efi_secure_launch(boot_params); > + > /* > * Call the SEV init code while still running with the firmware's > * GDT/IDT, so #VC exceptions will be handled by EFI. > -- > 2.39.3 >
Hi Ross, kernel test robot noticed the following build errors: [auto build test ERROR on char-misc/char-misc-testing] [also build test ERROR on char-misc/char-misc-next char-misc/char-misc-linus herbert-cryptodev-2.6/master herbert-crypto-2.6/master linus/master v6.8-rc4 next-20240216] [cannot apply to tip/x86/core] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Ross-Philipson/x86-boot-Place-kernel_info-at-a-fixed-offset/20240215-064712 base: char-misc/char-misc-testing patch link: https://lore.kernel.org/r/20240214221847.2066632-16-ross.philipson%40oracle.com patch subject: [PATCH v8 15/15] x86: EFI stub DRTM launch support for Secure Launch config: i386-randconfig-052-20240215 (https://download.01.org/0day-ci/archive/20240217/202402171503.kLhNHtkM-lkp@intel.com/config) compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240217/202402171503.kLhNHtkM-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202402171503.kLhNHtkM-lkp@intel.com/ All errors (new ones prefixed by >>): >> drivers/firmware/efi/libstub/x86-stub.c:862:18: error: invalid input size for constraint 'a' 862 | : : "a" (dlinfo->dl_handler), "D" (&dlinfo->bl_context)); | ^ 1 error generated. vim +/a +862 drivers/firmware/efi/libstub/x86-stub.c 813 814 static void efi_secure_launch(struct boot_params *boot_params) 815 { 816 struct slr_entry_uefi_config *uefi_config; 817 struct slr_uefi_cfg_entry *uefi_entry; 818 struct slr_entry_dl_info *dlinfo; 819 efi_guid_t guid = SLR_TABLE_GUID; 820 struct slr_table *slrt; 821 u64 memmap_hi; 822 void *table; 823 u8 buf[64] = {0}; 824 825 table = get_efi_config_table(guid); 826 827 /* 828 * The presence of this table indicated a Secure Launch 829 * is being requested. 830 */ 831 if (!table) 832 return; 833 834 slrt = (struct slr_table *)table; 835 836 if (slrt->magic != SLR_TABLE_MAGIC) 837 return; 838 839 /* Add config information to measure the UEFI memory map */ 840 uefi_config = (struct slr_entry_uefi_config *)buf; 841 uefi_config->hdr.tag = SLR_ENTRY_UEFI_CONFIG; 842 uefi_config->hdr.size = sizeof(*uefi_config) + sizeof(*uefi_entry); 843 uefi_config->revision = SLR_UEFI_CONFIG_REVISION; 844 uefi_config->nr_entries = 1; 845 uefi_entry = (struct slr_uefi_cfg_entry *)(buf + sizeof(*uefi_config)); 846 uefi_entry->pcr = 18; 847 uefi_entry->cfg = boot_params->efi_info.efi_memmap; 848 memmap_hi = boot_params->efi_info.efi_memmap_hi; 849 uefi_entry->cfg |= memmap_hi << 32; 850 uefi_entry->size = boot_params->efi_info.efi_memmap_size; 851 memcpy(&uefi_entry->evt_info[0], "Measured UEFI memory map", 852 strlen("Measured UEFI memory map")); 853 854 if (slr_add_entry(slrt, (struct slr_entry_hdr *)uefi_config)) 855 return; 856 857 /* Jump through DL stub to initiate Secure Launch */ 858 dlinfo = (struct slr_entry_dl_info *) 859 slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); 860 861 asm volatile ("jmp *%%rax" > 862 : : "a" (dlinfo->dl_handler), "D" (&dlinfo->bl_context)); 863 } 864
Hi Ross,
kernel test robot noticed the following build errors:
[auto build test ERROR on char-misc/char-misc-testing]
[also build test ERROR on char-misc/char-misc-next char-misc/char-misc-linus herbert-cryptodev-2.6/master herbert-crypto-2.6/master linus/master v6.8-rc4 next-20240216]
[cannot apply to tip/x86/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Ross-Philipson/x86-boot-Place-kernel_info-at-a-fixed-offset/20240215-064712
base: char-misc/char-misc-testing
patch link: https://lore.kernel.org/r/20240214221847.2066632-16-ross.philipson%40oracle.com
patch subject: [PATCH v8 15/15] x86: EFI stub DRTM launch support for Secure Launch
config: i386-allmodconfig (https://download.01.org/0day-ci/archive/20240218/202402180324.a3PqEegg-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240218/202402180324.a3PqEegg-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202402180324.a3PqEegg-lkp@intel.com/
All errors (new ones prefixed by >>):
In function 'efi_secure_launch',
inlined from 'efi_stub_entry' at drivers/firmware/efi/libstub/x86-stub.c:990:2:
>> drivers/firmware/efi/libstub/x86-stub.c:861:9: error: inconsistent operand constraints in an 'asm'
861 | asm volatile ("jmp *%%rax"
| ^~~
vim +/asm +861 drivers/firmware/efi/libstub/x86-stub.c
813
814 static void efi_secure_launch(struct boot_params *boot_params)
815 {
816 struct slr_entry_uefi_config *uefi_config;
817 struct slr_uefi_cfg_entry *uefi_entry;
818 struct slr_entry_dl_info *dlinfo;
819 efi_guid_t guid = SLR_TABLE_GUID;
820 struct slr_table *slrt;
821 u64 memmap_hi;
822 void *table;
823 u8 buf[64] = {0};
824
825 table = get_efi_config_table(guid);
826
827 /*
828 * The presence of this table indicated a Secure Launch
829 * is being requested.
830 */
831 if (!table)
832 return;
833
834 slrt = (struct slr_table *)table;
835
836 if (slrt->magic != SLR_TABLE_MAGIC)
837 return;
838
839 /* Add config information to measure the UEFI memory map */
840 uefi_config = (struct slr_entry_uefi_config *)buf;
841 uefi_config->hdr.tag = SLR_ENTRY_UEFI_CONFIG;
842 uefi_config->hdr.size = sizeof(*uefi_config) + sizeof(*uefi_entry);
843 uefi_config->revision = SLR_UEFI_CONFIG_REVISION;
844 uefi_config->nr_entries = 1;
845 uefi_entry = (struct slr_uefi_cfg_entry *)(buf + sizeof(*uefi_config));
846 uefi_entry->pcr = 18;
847 uefi_entry->cfg = boot_params->efi_info.efi_memmap;
848 memmap_hi = boot_params->efi_info.efi_memmap_hi;
849 uefi_entry->cfg |= memmap_hi << 32;
850 uefi_entry->size = boot_params->efi_info.efi_memmap_size;
851 memcpy(&uefi_entry->evt_info[0], "Measured UEFI memory map",
852 strlen("Measured UEFI memory map"));
853
854 if (slr_add_entry(slrt, (struct slr_entry_hdr *)uefi_config))
855 return;
856
857 /* Jump through DL stub to initiate Secure Launch */
858 dlinfo = (struct slr_entry_dl_info *)
859 slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO);
860
> 861 asm volatile ("jmp *%%rax"
862 : : "a" (dlinfo->dl_handler), "D" (&dlinfo->bl_context));
863 }
864
On 2/15/24 1:01 AM, Ard Biesheuvel wrote: > On Wed, 14 Feb 2024 at 23:32, Ross Philipson <ross.philipson@oracle.com> wrote: >> >> This support allows the DRTM launch to be initiated after an EFI stub >> launch of the Linux kernel is done. This is accomplished by providing >> a handler to jump to when a Secure Launch is in progress. This has to be >> called after the EFI stub does Exit Boot Services. >> >> Signed-off-by: Ross Philipson <ross.philipson@oracle.com> >> --- >> drivers/firmware/efi/libstub/x86-stub.c | 55 +++++++++++++++++++++++++ >> 1 file changed, 55 insertions(+) >> >> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c >> index 0d510c9a06a4..4df2cf539194 100644 >> --- a/drivers/firmware/efi/libstub/x86-stub.c >> +++ b/drivers/firmware/efi/libstub/x86-stub.c >> @@ -9,6 +9,7 @@ >> #include <linux/efi.h> >> #include <linux/pci.h> >> #include <linux/stddef.h> >> +#include <linux/slr_table.h> >> >> #include <asm/efi.h> >> #include <asm/e820/types.h> >> @@ -810,6 +811,57 @@ static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry) >> return EFI_SUCCESS; >> } >> >> +static void efi_secure_launch(struct boot_params *boot_params) >> +{ >> + struct slr_entry_uefi_config *uefi_config; >> + struct slr_uefi_cfg_entry *uefi_entry; >> + struct slr_entry_dl_info *dlinfo; >> + efi_guid_t guid = SLR_TABLE_GUID; >> + struct slr_table *slrt; >> + u64 memmap_hi; >> + void *table; >> + u8 buf[64] = {0}; >> + > > If you add a flex array to slr_entry_uefi_config as I suggested in > response to the other patch, we could simplify this substantially I feel like there is some reason why we did not use flex arrays. We were talking and we seem to remember we used to use them and someone asked us to remove them. We are still looking into it. But if we can go back to them, I will take all the changes you recommended here. Thanks Ross > > static struct slr_entry_uefi_config cfg = { > .hdr.tag = SLR_ENTRY_UEFI_CONFIG, > .hdr.size = sizeof(cfg), > .revision = SLR_UEFI_CONFIG_REVISION, > .nr_entries = 1, > .entries[0] = { > .pcr = 18, > .evt_info = "Measured UEFI memory map", > }, > }; > > cfg.entries[0].cfg = boot_params->efi_info.efi_memmap | > (u64)boot_params->efi_info.efi_memmap_hi << 32; > cfg.entries[0].size = boot_params->efi_info.efi_memmap_size; > > > >> + table = get_efi_config_table(guid); >> + >> + /* >> + * The presence of this table indicated a Secure Launch >> + * is being requested. >> + */ >> + if (!table) >> + return; >> + >> + slrt = (struct slr_table *)table; >> + >> + if (slrt->magic != SLR_TABLE_MAGIC) >> + return; >> + > > slrt = (struct slr_table *)get_efi_config_table(guid); > if (!slrt || slrt->magic != SLR_TABLE_MAGIC) > return; > >> + /* Add config information to measure the UEFI memory map */ >> + uefi_config = (struct slr_entry_uefi_config *)buf; >> + uefi_config->hdr.tag = SLR_ENTRY_UEFI_CONFIG; >> + uefi_config->hdr.size = sizeof(*uefi_config) + sizeof(*uefi_entry); >> + uefi_config->revision = SLR_UEFI_CONFIG_REVISION; >> + uefi_config->nr_entries = 1; >> + uefi_entry = (struct slr_uefi_cfg_entry *)(buf + sizeof(*uefi_config)); >> + uefi_entry->pcr = 18; >> + uefi_entry->cfg = boot_params->efi_info.efi_memmap; >> + memmap_hi = boot_params->efi_info.efi_memmap_hi; >> + uefi_entry->cfg |= memmap_hi << 32; >> + uefi_entry->size = boot_params->efi_info.efi_memmap_size; >> + memcpy(&uefi_entry->evt_info[0], "Measured UEFI memory map", >> + strlen("Measured UEFI memory map")); >> + > > Drop all of this > >> + if (slr_add_entry(slrt, (struct slr_entry_hdr *)uefi_config)) > > if (slr_add_entry(slrt, &uefi_config.hdr)) > > >> + return; >> + >> + /* Jump through DL stub to initiate Secure Launch */ >> + dlinfo = (struct slr_entry_dl_info *) >> + slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); >> + >> + asm volatile ("jmp *%%rax" >> + : : "a" (dlinfo->dl_handler), "D" (&dlinfo->bl_context)); > > Fix the prototype and just do > > dlinfo->dl_handler(&dlinfo->bl_context); > unreachable(); > > > So in summary, this becomes > > static void efi_secure_launch(struct boot_params *boot_params) > { > static struct slr_entry_uefi_config cfg = { > .hdr.tag = SLR_ENTRY_UEFI_CONFIG, > .hdr.size = sizeof(cfg), > .revision = SLR_UEFI_CONFIG_REVISION, > .nr_entries = 1, > .entries[0] = { > .pcr = 18, > .evt_info = "Measured UEFI memory map", > }, > }; > struct slr_entry_dl_info *dlinfo; > efi_guid_t guid = SLR_TABLE_GUID; > struct slr_table *slrt; > > /* > * The presence of this table indicated a Secure Launch > * is being requested. > */ > slrt = (struct slr_table *)get_efi_config_table(guid); > if (!slrt || slrt->magic != SLR_TABLE_MAGIC) > return; > > cfg.entries[0].cfg = boot_params->efi_info.efi_memmap | > (u64)boot_params->efi_info.efi_memmap_hi << 32; > cfg.entries[0].size = boot_params->efi_info.efi_memmap_size; > > if (slr_add_entry(slrt, &cfg.hdr)) > return; > > /* Jump through DL stub to initiate Secure Launch */ > dlinfo = (struct slr_entry_dl_info *) > slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); > > dlinfo->dl_handler(&dlinfo->bl_context); > > unreachable(); > } > > >> +} >> + >> static void __noreturn enter_kernel(unsigned long kernel_addr, >> struct boot_params *boot_params) >> { >> @@ -934,6 +986,9 @@ void __noreturn efi_stub_entry(efi_handle_t handle, >> goto fail; >> } >> >> + /* If a Secure Launch is in progress, this never returns */ > > if (IS_ENABLED(CONFIG_SECURE_LAUNCH)) > >> + efi_secure_launch(boot_params); >> + >> /* >> * Call the SEV init code while still running with the firmware's >> * GDT/IDT, so #VC exceptions will be handled by EFI. >> -- >> 2.39.3 >> >
On February 21, 2024 12:17:30 PM PST, ross.philipson@oracle.com wrote: >On 2/15/24 1:01 AM, Ard Biesheuvel wrote: >> On Wed, 14 Feb 2024 at 23:32, Ross Philipson <ross.philipson@oracle.com> wrote: >>> >>> This support allows the DRTM launch to be initiated after an EFI stub >>> launch of the Linux kernel is done. This is accomplished by providing >>> a handler to jump to when a Secure Launch is in progress. This has to be >>> called after the EFI stub does Exit Boot Services. >>> >>> Signed-off-by: Ross Philipson <ross.philipson@oracle.com> >>> --- >>> drivers/firmware/efi/libstub/x86-stub.c | 55 +++++++++++++++++++++++++ >>> 1 file changed, 55 insertions(+) >>> >>> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c >>> index 0d510c9a06a4..4df2cf539194 100644 >>> --- a/drivers/firmware/efi/libstub/x86-stub.c >>> +++ b/drivers/firmware/efi/libstub/x86-stub.c >>> @@ -9,6 +9,7 @@ >>> #include <linux/efi.h> >>> #include <linux/pci.h> >>> #include <linux/stddef.h> >>> +#include <linux/slr_table.h> >>> >>> #include <asm/efi.h> >>> #include <asm/e820/types.h> >>> @@ -810,6 +811,57 @@ static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry) >>> return EFI_SUCCESS; >>> } >>> >>> +static void efi_secure_launch(struct boot_params *boot_params) >>> +{ >>> + struct slr_entry_uefi_config *uefi_config; >>> + struct slr_uefi_cfg_entry *uefi_entry; >>> + struct slr_entry_dl_info *dlinfo; >>> + efi_guid_t guid = SLR_TABLE_GUID; >>> + struct slr_table *slrt; >>> + u64 memmap_hi; >>> + void *table; >>> + u8 buf[64] = {0}; >>> + >> >> If you add a flex array to slr_entry_uefi_config as I suggested in >> response to the other patch, we could simplify this substantially > >I feel like there is some reason why we did not use flex arrays. We were talking and we seem to remember we used to use them and someone asked us to remove them. We are still looking into it. But if we can go back to them, I will take all the changes you recommended here. > >Thanks >Ross > >> >> static struct slr_entry_uefi_config cfg = { >> .hdr.tag = SLR_ENTRY_UEFI_CONFIG, >> .hdr.size = sizeof(cfg), >> .revision = SLR_UEFI_CONFIG_REVISION, >> .nr_entries = 1, >> .entries[0] = { >> .pcr = 18, >> .evt_info = "Measured UEFI memory map", >> }, >> }; >> >> cfg.entries[0].cfg = boot_params->efi_info.efi_memmap | >> (u64)boot_params->efi_info.efi_memmap_hi << 32; >> cfg.entries[0].size = boot_params->efi_info.efi_memmap_size; >> >> >> >>> + table = get_efi_config_table(guid); >>> + >>> + /* >>> + * The presence of this table indicated a Secure Launch >>> + * is being requested. >>> + */ >>> + if (!table) >>> + return; >>> + >>> + slrt = (struct slr_table *)table; >>> + >>> + if (slrt->magic != SLR_TABLE_MAGIC) >>> + return; >>> + >> >> slrt = (struct slr_table *)get_efi_config_table(guid); >> if (!slrt || slrt->magic != SLR_TABLE_MAGIC) >> return; >> >>> + /* Add config information to measure the UEFI memory map */ >>> + uefi_config = (struct slr_entry_uefi_config *)buf; >>> + uefi_config->hdr.tag = SLR_ENTRY_UEFI_CONFIG; >>> + uefi_config->hdr.size = sizeof(*uefi_config) + sizeof(*uefi_entry); >>> + uefi_config->revision = SLR_UEFI_CONFIG_REVISION; >>> + uefi_config->nr_entries = 1; >>> + uefi_entry = (struct slr_uefi_cfg_entry *)(buf + sizeof(*uefi_config)); >>> + uefi_entry->pcr = 18; >>> + uefi_entry->cfg = boot_params->efi_info.efi_memmap; >>> + memmap_hi = boot_params->efi_info.efi_memmap_hi; >>> + uefi_entry->cfg |= memmap_hi << 32; >>> + uefi_entry->size = boot_params->efi_info.efi_memmap_size; >>> + memcpy(&uefi_entry->evt_info[0], "Measured UEFI memory map", >>> + strlen("Measured UEFI memory map")); >>> + >> >> Drop all of this >> >>> + if (slr_add_entry(slrt, (struct slr_entry_hdr *)uefi_config)) >> >> if (slr_add_entry(slrt, &uefi_config.hdr)) >> >> >>> + return; >>> + >>> + /* Jump through DL stub to initiate Secure Launch */ >>> + dlinfo = (struct slr_entry_dl_info *) >>> + slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); >>> + >>> + asm volatile ("jmp *%%rax" >>> + : : "a" (dlinfo->dl_handler), "D" (&dlinfo->bl_context)); >> >> Fix the prototype and just do >> >> dlinfo->dl_handler(&dlinfo->bl_context); >> unreachable(); >> >> >> So in summary, this becomes >> >> static void efi_secure_launch(struct boot_params *boot_params) >> { >> static struct slr_entry_uefi_config cfg = { >> .hdr.tag = SLR_ENTRY_UEFI_CONFIG, >> .hdr.size = sizeof(cfg), >> .revision = SLR_UEFI_CONFIG_REVISION, >> .nr_entries = 1, >> .entries[0] = { >> .pcr = 18, >> .evt_info = "Measured UEFI memory map", >> }, >> }; >> struct slr_entry_dl_info *dlinfo; >> efi_guid_t guid = SLR_TABLE_GUID; >> struct slr_table *slrt; >> >> /* >> * The presence of this table indicated a Secure Launch >> * is being requested. >> */ >> slrt = (struct slr_table *)get_efi_config_table(guid); >> if (!slrt || slrt->magic != SLR_TABLE_MAGIC) >> return; >> >> cfg.entries[0].cfg = boot_params->efi_info.efi_memmap | >> (u64)boot_params->efi_info.efi_memmap_hi << 32; >> cfg.entries[0].size = boot_params->efi_info.efi_memmap_size; >> >> if (slr_add_entry(slrt, &cfg.hdr)) >> return; >> >> /* Jump through DL stub to initiate Secure Launch */ >> dlinfo = (struct slr_entry_dl_info *) >> slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); >> >> dlinfo->dl_handler(&dlinfo->bl_context); >> >> unreachable(); >> } >> >> >>> +} >>> + >>> static void __noreturn enter_kernel(unsigned long kernel_addr, >>> struct boot_params *boot_params) >>> { >>> @@ -934,6 +986,9 @@ void __noreturn efi_stub_entry(efi_handle_t handle, >>> goto fail; >>> } >>> >>> + /* If a Secure Launch is in progress, this never returns */ >> >> if (IS_ENABLED(CONFIG_SECURE_LAUNCH)) >> >>> + efi_secure_launch(boot_params); >>> + >>> /* >>> * Call the SEV init code while still running with the firmware's >>> * GDT/IDT, so #VC exceptions will be handled by EFI. >>> -- >>> 2.39.3 >>> >> > Linux kernel code doesn't use VLAs because of the limited stack size, and VLAs or alloca() makes stack size tracking impossible. Although this technically speaking runs in a different environment, it is easier to enforce the constraint globally.
On Wed, 21 Feb 2024 at 21:37, H. Peter Anvin <hpa@zytor.com> wrote: > > On February 21, 2024 12:17:30 PM PST, ross.philipson@oracle.com wrote: > >On 2/15/24 1:01 AM, Ard Biesheuvel wrote: > >> On Wed, 14 Feb 2024 at 23:32, Ross Philipson <ross.philipson@oracle.com> wrote: > >>> > >>> This support allows the DRTM launch to be initiated after an EFI stub > >>> launch of the Linux kernel is done. This is accomplished by providing > >>> a handler to jump to when a Secure Launch is in progress. This has to be > >>> called after the EFI stub does Exit Boot Services. > >>> > >>> Signed-off-by: Ross Philipson <ross.philipson@oracle.com> > >>> --- > >>> drivers/firmware/efi/libstub/x86-stub.c | 55 +++++++++++++++++++++++++ > >>> 1 file changed, 55 insertions(+) > >>> > >>> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c > >>> index 0d510c9a06a4..4df2cf539194 100644 > >>> --- a/drivers/firmware/efi/libstub/x86-stub.c > >>> +++ b/drivers/firmware/efi/libstub/x86-stub.c > >>> @@ -9,6 +9,7 @@ > >>> #include <linux/efi.h> > >>> #include <linux/pci.h> > >>> #include <linux/stddef.h> > >>> +#include <linux/slr_table.h> > >>> > >>> #include <asm/efi.h> > >>> #include <asm/e820/types.h> > >>> @@ -810,6 +811,57 @@ static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry) > >>> return EFI_SUCCESS; > >>> } > >>> > >>> +static void efi_secure_launch(struct boot_params *boot_params) > >>> +{ > >>> + struct slr_entry_uefi_config *uefi_config; > >>> + struct slr_uefi_cfg_entry *uefi_entry; > >>> + struct slr_entry_dl_info *dlinfo; > >>> + efi_guid_t guid = SLR_TABLE_GUID; > >>> + struct slr_table *slrt; > >>> + u64 memmap_hi; > >>> + void *table; > >>> + u8 buf[64] = {0}; > >>> + > >> > >> If you add a flex array to slr_entry_uefi_config as I suggested in > >> response to the other patch, we could simplify this substantially > > > >I feel like there is some reason why we did not use flex arrays. We were talking and we seem to remember we used to use them and someone asked us to remove them. We are still looking into it. But if we can go back to them, I will take all the changes you recommended here. > > > > Linux kernel code doesn't use VLAs because of the limited stack size, and VLAs or alloca() makes stack size tracking impossible. Although this technically speaking runs in a different environment, it is easier to enforce the constraint globally. Flex array != VLA VLAs were phased out because of this reason (and VLAISs [VLAs in structs] were phased out before that because they are a GNU extension and not supported by Clang) Today, VLAs are not supported anywhere in the kernel. Flex arrays are widely used in the kernel. A flex array is a trailing array of unspecified size in a struct that makes the entire *type* have a variable size. But that does not make them VLAs (or VLAISs) - a VLA is a stack allocated *variable* whose size is based on a function parameter. Instances of types containing flex arrays can be allocated statically, or dynamically on the heap. This is common practice in the kernel, and even supported by instrumentation to help the compiler track the runtime size and flag overruns. We are even in the process of adding compiler support to annotate struct members as carrying the number of elements in an associated flex arrays, to improve the coverage of the instrumentation. I am not asking for a VLA here, only a flex array.
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index 0d510c9a06a4..4df2cf539194 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -9,6 +9,7 @@ #include <linux/efi.h> #include <linux/pci.h> #include <linux/stddef.h> +#include <linux/slr_table.h> #include <asm/efi.h> #include <asm/e820/types.h> @@ -810,6 +811,57 @@ static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry) return EFI_SUCCESS; } +static void efi_secure_launch(struct boot_params *boot_params) +{ + struct slr_entry_uefi_config *uefi_config; + struct slr_uefi_cfg_entry *uefi_entry; + struct slr_entry_dl_info *dlinfo; + efi_guid_t guid = SLR_TABLE_GUID; + struct slr_table *slrt; + u64 memmap_hi; + void *table; + u8 buf[64] = {0}; + + table = get_efi_config_table(guid); + + /* + * The presence of this table indicated a Secure Launch + * is being requested. + */ + if (!table) + return; + + slrt = (struct slr_table *)table; + + if (slrt->magic != SLR_TABLE_MAGIC) + return; + + /* Add config information to measure the UEFI memory map */ + uefi_config = (struct slr_entry_uefi_config *)buf; + uefi_config->hdr.tag = SLR_ENTRY_UEFI_CONFIG; + uefi_config->hdr.size = sizeof(*uefi_config) + sizeof(*uefi_entry); + uefi_config->revision = SLR_UEFI_CONFIG_REVISION; + uefi_config->nr_entries = 1; + uefi_entry = (struct slr_uefi_cfg_entry *)(buf + sizeof(*uefi_config)); + uefi_entry->pcr = 18; + uefi_entry->cfg = boot_params->efi_info.efi_memmap; + memmap_hi = boot_params->efi_info.efi_memmap_hi; + uefi_entry->cfg |= memmap_hi << 32; + uefi_entry->size = boot_params->efi_info.efi_memmap_size; + memcpy(&uefi_entry->evt_info[0], "Measured UEFI memory map", + strlen("Measured UEFI memory map")); + + if (slr_add_entry(slrt, (struct slr_entry_hdr *)uefi_config)) + return; + + /* Jump through DL stub to initiate Secure Launch */ + dlinfo = (struct slr_entry_dl_info *) + slr_next_entry_by_tag(slrt, NULL, SLR_ENTRY_DL_INFO); + + asm volatile ("jmp *%%rax" + : : "a" (dlinfo->dl_handler), "D" (&dlinfo->bl_context)); +} + static void __noreturn enter_kernel(unsigned long kernel_addr, struct boot_params *boot_params) { @@ -934,6 +986,9 @@ void __noreturn efi_stub_entry(efi_handle_t handle, goto fail; } + /* If a Secure Launch is in progress, this never returns */ + efi_secure_launch(boot_params); + /* * Call the SEV init code while still running with the firmware's * GDT/IDT, so #VC exceptions will be handled by EFI.
This support allows the DRTM launch to be initiated after an EFI stub launch of the Linux kernel is done. This is accomplished by providing a handler to jump to when a Secure Launch is in progress. This has to be called after the EFI stub does Exit Boot Services. Signed-off-by: Ross Philipson <ross.philipson@oracle.com> --- drivers/firmware/efi/libstub/x86-stub.c | 55 +++++++++++++++++++++++++ 1 file changed, 55 insertions(+)