Re: [PATCH v12 03/19] x86: Secure Launch Resource Table header file

[ross.philipson@oracle.com]

On 3/6/25 9:32 PM, Jarkko Sakkinen wrote:
> On Thu, Dec 19, 2024 at 11:42:00AM -0800, Ross Philipson wrote:
>> Introduce the Secure Launch Resource Table which forms the formal
>> interface between the pre and post launch code.
>>
>> Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
> 
> Is this interface kernel specific or uarch specific? I'd just
> explicitly state the context of the formal interface, that's
> all.

It is specific to our DRTM solution (i.e. Secure Launch). It is meant to 
be extensible to accommodate future architectures that have DRTM support 
available. Not sure if I am getting at your specific question.

> 
>> ---
>>   include/linux/slr_table.h | 277 ++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 277 insertions(+)
>>   create mode 100644 include/linux/slr_table.h
>>
>> diff --git a/include/linux/slr_table.h b/include/linux/slr_table.h
>> new file mode 100644
>> index 000000000000..48d85d505a50
>> --- /dev/null
>> +++ b/include/linux/slr_table.h
>> @@ -0,0 +1,277 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * TrenchBoot Secure Launch Resource Table
>> + *
>> + * The Secure Launch Resource Table is TrenchBoot project defined
>> + * specfication to provide cross-architecture compatibility. See
>> + * TrenchBoot Secure Launch kernel documentation for details.
>> + *
>> + * Copyright (c) 2024 Apertus Solutions, LLC
>> + * Copyright (c) 2024, Oracle and/or its affiliates.
>> + */
>> +
>> +#ifndef _LINUX_SLR_TABLE_H
>> +#define _LINUX_SLR_TABLE_H
>> +
>> +/* Put this in efi.h if it becomes a standard */
>> +#define SLR_TABLE_GUID				EFI_GUID(0x877a9b2a, 0x0385, 0x45d1, 0xa0, 0x34, 0x9d, 0xac, 0x9c, 0x9e, 0x56, 0x5f)
>> +
>> +/* SLR table header values */
>> +#define SLR_TABLE_MAGIC		0x4452544d
>> +#define SLR_TABLE_REVISION	1
>> +
>> +/* Current revisions for the policy and UEFI config */
>> +#define SLR_POLICY_REVISION		1
>> +#define SLR_UEFI_CONFIG_REVISION	1
>> +
>> +/* SLR defined architectures */
>> +#define SLR_INTEL_TXT		1
>> +#define SLR_AMD_SKINIT		2
>> +
>> +/* SLR defined bootloaders */
>> +#define SLR_BOOTLOADER_INVALID	0
>> +#define SLR_BOOTLOADER_GRUB	1
>> +
>> +/* Log formats */
>> +#define SLR_DRTM_TPM12_LOG	1
>> +#define SLR_DRTM_TPM20_LOG	2
>> +
>> +/* DRTM Policy Entry Flags */
>> +#define SLR_POLICY_FLAG_MEASURED	0x1
>> +#define SLR_POLICY_IMPLICIT_SIZE	0x2
>> +
>> +/* Array Lengths */
>> +#define TPM_EVENT_INFO_LENGTH		32
>> +#define TXT_VARIABLE_MTRRS_LENGTH	32
>> +
>> +/* Tags */
>> +#define SLR_ENTRY_INVALID	0x0000
>> +#define SLR_ENTRY_DL_INFO	0x0001
>> +#define SLR_ENTRY_LOG_INFO	0x0002
>> +#define SLR_ENTRY_ENTRY_POLICY	0x0003
>> +#define SLR_ENTRY_INTEL_INFO	0x0004
>> +#define SLR_ENTRY_AMD_INFO	0x0005
>> +#define SLR_ENTRY_ARM_INFO	0x0006
>> +#define SLR_ENTRY_UEFI_INFO	0x0007
>> +#define SLR_ENTRY_UEFI_CONFIG	0x0008
>> +#define SLR_ENTRY_END		0xffff
>> +
>> +/* Entity Types */
>> +#define SLR_ET_UNSPECIFIED	0x0000
>> +#define SLR_ET_SLRT		0x0001
>> +#define SLR_ET_BOOT_PARAMS	0x0002
>> +#define SLR_ET_SETUP_DATA	0x0003
>> +#define SLR_ET_CMDLINE		0x0004
>> +#define SLR_ET_UEFI_MEMMAP	0x0005
>> +#define SLR_ET_RAMDISK		0x0006
>> +#define SLR_ET_TXT_OS2MLE	0x0010
>> +#define SLR_ET_UNUSED		0xffff
>> +
>> +#ifndef __ASSEMBLY__
>> +
>> +/*
>> + * Primary Secure Launch Resource Table Header
>> + */
>> +struct slr_table {
>> +	u32 magic;
>> +	u16 revision;
>> +	u16 architecture;
>> +	u32 size;
>> +	u32 max_size;
>> +	/* table entries */
>> +} __packed;
>> +
>> +/*
>> + * Common SLRT Table Header
>> + */
>> +struct slr_entry_hdr {
>> +	u32 tag;
>> +	u32 size;
>> +} __packed;
>> +
>> +/*
>> + * Boot loader context
>> + */
>> +struct slr_bl_context {
>> +	u16 bootloader;
>> +	u16 reserved[3];
>> +	u64 context;
>> +} __packed;
>> +
>> +/*
>> + * Dynamic Launch Callback Function type
>> + */
>> +typedef void (*dl_handler_func)(struct slr_bl_context *bl_context);
>> +
>> +/*
>> + * DRTM Dynamic Launch Configuration
>> + */
>> +struct slr_entry_dl_info {
>> +	struct slr_entry_hdr hdr;
>> +	u64 dce_size;
>> +	u64 dce_base;
>> +	u64 dlme_size;
>> +	u64 dlme_base;
>> +	u64 dlme_entry;
>> +	struct slr_bl_context bl_context;
>> +	u64 dl_handler;
>> +} __packed;
>> +
>> +/*
>> + * TPM Log Information
>> + */
>> +struct slr_entry_log_info {
>> +	struct slr_entry_hdr hdr;
>> +	u16 format;
>> +	u16 reserved;
>> +	u32 size;
>> +	u64 addr;
>> +} __packed;
>> +
>> +/*
>> + * DRTM Measurement Entry
>> + */
>> +struct slr_policy_entry {
>> +	u16 pcr;
>> +	u16 entity_type;
>> +	u16 flags;
>> +	u16 reserved;
>> +	u64 size;
>> +	u64 entity;
>> +	char evt_info[TPM_EVENT_INFO_LENGTH];
>> +} __packed;
>> +
>> +/*
>> + * DRTM Measurement Policy
>> + */
>> +struct slr_entry_policy {
>> +	struct slr_entry_hdr hdr;
>> +	u16 reserved[2];
>> +	u16 revision;
>> +	u16 nr_entries;
>> +	struct slr_policy_entry policy_entries[];
>> +} __packed;
>> +
>> +/*
>> + * Secure Launch defined MTRR saving structures
>> + */
>> +struct slr_txt_mtrr_pair {
>> +	u64 mtrr_physbase;
>> +	u64 mtrr_physmask;
>> +} __packed;
>> +
>> +struct slr_txt_mtrr_state {
>> +	u64 default_mem_type;
>> +	u64 mtrr_vcnt;
>> +	struct slr_txt_mtrr_pair mtrr_pair[TXT_VARIABLE_MTRRS_LENGTH];
>> +} __packed;
>> +
>> +/*
>> + * Intel TXT Info table
>> + */
>> +struct slr_entry_intel_info {
>> +	struct slr_entry_hdr hdr;
>> +	u64 boot_params_addr;
>> +	u64 txt_heap;
>> +	u64 saved_misc_enable_msr;
>> +	struct slr_txt_mtrr_state saved_bsp_mtrrs;
>> +} __packed;
>> +
>> +/*
>> + * UEFI config measurement entry
>> + */
>> +struct slr_uefi_cfg_entry {
>> +	u16 pcr;
>> +	u16 reserved;
>> +	u32 size;
>> +	u64 cfg; /* address or value */
>> +	char evt_info[TPM_EVENT_INFO_LENGTH];
>> +} __packed;
>> +
>> +/*
>> + * UEFI config measurements
>> + */
>> +struct slr_entry_uefi_config {
>> +	struct slr_entry_hdr hdr;
>> +	u16 reserved[2];
>> +	u16 revision;
>> +	u16 nr_entries;
>> +	struct slr_uefi_cfg_entry uefi_cfg_entries[];
>> +} __packed;
>> +
>> +static inline void *slr_end_of_entries(struct slr_table *table)
> 
> I'd document these functions. No need to go over the top here i.e.,
> no need to have full parameter descriptions but more like

Will do. Same for functions below.

Thank you,
Ross

> 
> /*
>   * Tell a short description.
>   */
> 
>> +{
>> +	return (void *)table + table->size;
>> +}
>> +
>> +static inline void *
>> +slr_next_entry(struct slr_table *table,
>> +	       struct slr_entry_hdr *curr)
>> +{
>> +	struct slr_entry_hdr *next = (struct slr_entry_hdr *)((u8 *)curr + curr->size);
>> +
>> +	if ((void *)next >= slr_end_of_entries(table))
>> +		return NULL;
>> +	if (next->tag == SLR_ENTRY_END)
>> +		return NULL;
>> +
>> +	return next;
>> +}
>> +
>> +static inline void *
>> +slr_next_entry_by_tag(struct slr_table *table,
>> +		      struct slr_entry_hdr *entry,
>> +		      u16 tag)
>> +{
>> +	if (!entry) /* Start from the beginning */
>> +		entry = (struct slr_entry_hdr *)(((u8 *)table) + sizeof(*table));
>> +
>> +	for ( ; ; ) {
>> +		if (entry->tag == tag)
>> +			return entry;
>> +
>> +		entry = slr_next_entry(table, entry);
>> +		if (!entry)
>> +			return NULL;
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +static inline int
>> +slr_add_entry(struct slr_table *table,
>> +	      struct slr_entry_hdr *entry)
>> +{
>> +	struct slr_entry_hdr *end;
>> +
>> +	if ((table->size + entry->size) > table->max_size)
>> +		return -1;
>> +
>> +	memcpy((u8 *)table + table->size - sizeof(*end), entry, entry->size);
>> +	table->size += entry->size;
>> +
>> +	end  = (struct slr_entry_hdr *)((u8 *)table + table->size - sizeof(*end));
>> +	end->tag = SLR_ENTRY_END;
>> +	end->size = sizeof(*end);
>> +
>> +	return 0;
>> +}
>> +
>> +static inline void
>> +slr_init_table(struct slr_table *slrt, u16 architecture, u32 max_size)
> 
> E.g., what does slr_init_table() do and why and when it is called. Basic
> shit.
> 
>> +{
>> +	struct slr_entry_hdr *end;
>> +
>> +	slrt->magic = SLR_TABLE_MAGIC;
>> +	slrt->revision = SLR_TABLE_REVISION;
>> +	slrt->architecture = architecture;
>> +	slrt->size = sizeof(*slrt) + sizeof(*end);
>> +	slrt->max_size = max_size;
>> +	end = (struct slr_entry_hdr *)((u8 *)slrt + sizeof(*slrt));
>> +	end->tag = SLR_ENTRY_END;
>> +	end->size = sizeof(*end);
>> +}
>> +
>> +#endif /* !__ASSEMBLY */
>> +
>> +#endif /* _LINUX_SLR_TABLE_H */
>> -- 
>> 2.39.3
>>
> 
> BR, Jarkko