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Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: Re: [PATCH Part1 v5 26/38] x86/compressed/acpi: move EFI config table access to common code Message-ID: References: <20210820151933.22401-1-brijesh.singh@amd.com> <20210820151933.22401-27-brijesh.singh@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210820151933.22401-27-brijesh.singh@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 20, 2021 at 10:19:21AM -0500, Brijesh Singh wrote: > From: Michael Roth > > Future patches for SEV-SNP-validated CPUID will also require early > parsing of the EFI configuration. Move the related code into a set of > helpers that can be re-used for that purpose. > > Signed-off-by: Michael Roth > Signed-off-by: Brijesh Singh > --- > arch/x86/boot/compressed/Makefile | 1 + > arch/x86/boot/compressed/acpi.c | 113 +++++-------------- > arch/x86/boot/compressed/efi.c | 178 ++++++++++++++++++++++++++++++ > arch/x86/boot/compressed/misc.h | 43 ++++++++ > 4 files changed, 251 insertions(+), 84 deletions(-) > create mode 100644 arch/x86/boot/compressed/efi.c Ok, better, but this patch needs splitting. And I have a good idea how: in at least three patches: 1. Add efi_get_system_table() and use it 2. Add efi_get_conf_table() and use it 3. Add efi_find_vendor_table() and use it This will facilitate review immensely. Also, here's a diff ontop of what to do also, style-wise. - change how you look for the preferred vendor table along with commenting what you do - shorten variable names so that you don't have so many line breaks. Thx. diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c index 3a3f997d7210..c22b21e94a95 100644 --- a/arch/x86/boot/compressed/acpi.c +++ b/arch/x86/boot/compressed/acpi.c @@ -20,27 +20,29 @@ */ struct mem_vector immovable_mem[MAX_NUMNODES*2]; -/* - * Search EFI system tables for RSDP. If both ACPI_20_TABLE_GUID and - * ACPI_TABLE_GUID are found, take the former, which has more features. - */ static acpi_physical_address -__efi_get_rsdp_addr(unsigned long config_table_pa, - unsigned int config_table_len, bool efi_64) +__efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len, bool efi_64) { acpi_physical_address rsdp_addr = 0; + #ifdef CONFIG_EFI int ret; - ret = efi_find_vendor_table(config_table_pa, config_table_len, - ACPI_20_TABLE_GUID, efi_64, - (unsigned long *)&rsdp_addr); - if (ret == -ENOENT) - ret = efi_find_vendor_table(config_table_pa, config_table_len, - ACPI_TABLE_GUID, efi_64, - (unsigned long *)&rsdp_addr); + /* + * Search EFI system tables for RSDP. Preferred is ACPI_20_TABLE_GUID to + * ACPI_TABLE_GUID because it has more features. + */ + ret = efi_find_vendor_table(cfg_tbl_pa, cfg_tbl_len, ACPI_20_TABLE_GUID, + efi_64, (unsigned long *)&rsdp_addr); + if (!ret) + return rsdp_addr; + + /* No ACPI_20_TABLE_GUID found, fallback to ACPI_TABLE_GUID. */ + ret = efi_find_vendor_table(cfg_tbl_pa, cfg_tbl_len, ACPI_TABLE_GUID, + efi_64, (unsigned long *)&rsdp_addr); if (ret) debug_putstr("Error getting RSDP address.\n"); + #endif return rsdp_addr; } @@ -100,18 +102,16 @@ static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; } static acpi_physical_address efi_get_rsdp_addr(void) { #ifdef CONFIG_EFI - unsigned long config_table_pa = 0; - unsigned int config_table_len; + unsigned long cfg_tbl_pa = 0; + unsigned int cfg_tbl_len; bool efi_64; int ret; - ret = efi_get_conf_table(boot_params, &config_table_pa, - &config_table_len, &efi_64); - if (ret || !config_table_pa) + ret = efi_get_conf_table(boot_params, &cfg_tbl_pa, &cfg_tbl_len, &efi_64); + if (ret || !cfg_tbl_pa) error("EFI config table not found."); - return __efi_get_rsdp_addr(config_table_pa, config_table_len, - efi_64); + return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len, efi_64); #else return 0; #endif diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c index 16ff5cb9a1fb..7ed31b943c04 100644 --- a/arch/x86/boot/compressed/efi.c +++ b/arch/x86/boot/compressed/efi.c @@ -12,14 +12,14 @@ #include /* Get vendor table address/guid from EFI config table at the given index */ -static int get_vendor_table(void *conf_table, unsigned int idx, +static int get_vendor_table(void *cfg_tbl, unsigned int idx, unsigned long *vendor_table_pa, efi_guid_t *vendor_table_guid, bool efi_64) { if (efi_64) { efi_config_table_64_t *table_entry = - (efi_config_table_64_t *)conf_table + idx; + (efi_config_table_64_t *)cfg_tbl + idx; if (!IS_ENABLED(CONFIG_X86_64) && table_entry->table >> 32) { @@ -32,7 +32,7 @@ static int get_vendor_table(void *conf_table, unsigned int idx, } else { efi_config_table_32_t *table_entry = - (efi_config_table_32_t *)conf_table + idx; + (efi_config_table_32_t *)cfg_tbl + idx; *vendor_table_pa = table_entry->table; *vendor_table_guid = table_entry->guid; @@ -45,27 +45,25 @@ static int get_vendor_table(void *conf_table, unsigned int idx, * Given EFI config table, search it for the physical address of the vendor * table associated with GUID. * - * @conf_table: pointer to EFI configuration table - * @conf_table_len: number of entries in EFI configuration table + * @cfg_tbl: pointer to EFI configuration table + * @cfg_tbl_len: number of entries in EFI configuration table * @guid: GUID of vendor table * @efi_64: true if using 64-bit EFI * @vendor_table_pa: location to store physical address of vendor table * * Returns 0 on success. On error, return params are left unchanged. */ -int -efi_find_vendor_table(unsigned long conf_table_pa, unsigned int conf_table_len, - efi_guid_t guid, bool efi_64, - unsigned long *vendor_table_pa) +int efi_find_vendor_table(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len, + efi_guid_t guid, bool efi_64, unsigned long *vendor_table_pa) { unsigned int i; - for (i = 0; i < conf_table_len; i++) { + for (i = 0; i < cfg_tbl_len; i++) { unsigned long vendor_table_pa_tmp; efi_guid_t vendor_table_guid; int ret; - if (get_vendor_table((void *)conf_table_pa, i, + if (get_vendor_table((void *)cfg_tbl_pa, i, &vendor_table_pa_tmp, &vendor_table_guid, efi_64)) return -EINVAL; @@ -88,9 +86,8 @@ efi_find_vendor_table(unsigned long conf_table_pa, unsigned int conf_table_len, * * Returns 0 on success. On error, return params are left unchanged. */ -int -efi_get_system_table(struct boot_params *boot_params, - unsigned long *sys_table_pa, bool *is_efi_64) +int efi_get_system_table(struct boot_params *boot_params, unsigned long *sys_table_pa, + bool *is_efi_64) { unsigned long sys_table; struct efi_info *ei; @@ -137,22 +134,19 @@ efi_get_system_table(struct boot_params *boot_params, * address EFI configuration table. * * @boot_params: pointer to boot_params - * @conf_table_pa: location to store physical address of config table - * @conf_table_len: location to store number of config table entries + * @cfg_tbl_pa: location to store physical address of config table + * @cfg_tbl_len: location to store number of config table entries * @is_efi_64: location to store whether using 64-bit EFI or not * * Returns 0 on success. On error, return params are left unchanged. */ -int -efi_get_conf_table(struct boot_params *boot_params, - unsigned long *conf_table_pa, - unsigned int *conf_table_len, - bool *is_efi_64) +int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa, + unsigned int *cfg_tbl_len, bool *is_efi_64) { unsigned long sys_table_pa = 0; int ret; - if (!conf_table_pa || !conf_table_len || !is_efi_64) + if (!cfg_tbl_pa || !cfg_tbl_len || !is_efi_64) return -EINVAL; ret = efi_get_system_table(boot_params, &sys_table_pa, is_efi_64); @@ -164,14 +158,14 @@ efi_get_conf_table(struct boot_params *boot_params, efi_system_table_64_t *stbl = (efi_system_table_64_t *)sys_table_pa; - *conf_table_pa = stbl->tables; - *conf_table_len = stbl->nr_tables; + *cfg_tbl_pa = stbl->tables; + *cfg_tbl_len = stbl->nr_tables; } else { efi_system_table_32_t *stbl = (efi_system_table_32_t *)sys_table_pa; - *conf_table_pa = stbl->tables; - *conf_table_len = stbl->nr_tables; + *cfg_tbl_pa = stbl->tables; + *cfg_tbl_len = stbl->nr_tables; } return 0; -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette