The kernel configures TDX usable memory regions to the TDX module via an array of "TD Memory Region" (TDMR). Each TDMR entry (TDMR_INFO) contains the information of the base/size of a memory region, the base/size of the associated Physical Address Metadata Table (PAMT) and a list of reserved areas in the region. Create a number of TDMRs according to the verified e820 RAM entries. As the first step only set up the base/size information for each TDMR. TDMR must be 1G aligned and the size must be in 1G granularity. This implies that one TDMR could cover multiple e820 RAM entries. If a RAM entry spans the 1GB boundary and the former part is already covered by the previous TDMR, just create a new TDMR for the latter part. TDX only supports a limited number of TDMRs (currently 64). Abort the TDMR construction process when the number of TDMRs exceeds this limitation. Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx> --- arch/x86/virt/vmx/tdx.c | 138 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) diff --git a/arch/x86/virt/vmx/tdx.c b/arch/x86/virt/vmx/tdx.c index e5206599f558..1939b64d23e8 100644 --- a/arch/x86/virt/vmx/tdx.c +++ b/arch/x86/virt/vmx/tdx.c @@ -54,6 +54,18 @@ ((u32)(((_keyid_part) & 0xffffffffull) + 1)) #define TDX_KEYID_NUM(_keyid_part) ((u32)((_keyid_part) >> 32)) +/* TDMR must be 1gb aligned */ +#define TDMR_ALIGNMENT BIT_ULL(30) +#define TDMR_PFN_ALIGNMENT (TDMR_ALIGNMENT >> PAGE_SHIFT) + +/* Align up and down the address to TDMR boundary */ +#define TDMR_ALIGN_DOWN(_addr) ALIGN_DOWN((_addr), TDMR_ALIGNMENT) +#define TDMR_ALIGN_UP(_addr) ALIGN((_addr), TDMR_ALIGNMENT) + +/* TDMR's start and end address */ +#define TDMR_START(_tdmr) ((_tdmr)->base) +#define TDMR_END(_tdmr) ((_tdmr)->base + (_tdmr)->size) + /* * TDX module status during initialization */ @@ -809,6 +821,44 @@ static int e820_check_against_cmrs(void) return 0; } +/* The starting offset of reserved areas within TDMR_INFO */ +#define TDMR_RSVD_START 64 + +static struct tdmr_info *__alloc_tdmr(void) +{ + int tdmr_sz; + + /* + * TDMR_INFO's actual size depends on maximum number of reserved + * areas that one TDMR supports. + */ + tdmr_sz = TDMR_RSVD_START + tdx_sysinfo.max_reserved_per_tdmr * + sizeof(struct tdmr_reserved_area); + + /* + * TDX requires TDMR_INFO to be 512 aligned. Always align up + * TDMR_INFO size to 512 so the memory allocated via kzalloc() + * can meet the alignment requirement. + */ + tdmr_sz = ALIGN(tdmr_sz, TDMR_INFO_ALIGNMENT); + + return kzalloc(tdmr_sz, GFP_KERNEL); +} + +/* Create a new TDMR at given index in the TDMR array */ +static struct tdmr_info *alloc_tdmr(struct tdmr_info **tdmr_array, int idx) +{ + struct tdmr_info *tdmr; + + if (WARN_ON_ONCE(tdmr_array[idx])) + return NULL; + + tdmr = __alloc_tdmr(); + tdmr_array[idx] = tdmr; + + return tdmr; +} + static void free_tdmrs(struct tdmr_info **tdmr_array, int tdmr_num) { int i; @@ -822,6 +872,89 @@ static void free_tdmrs(struct tdmr_info **tdmr_array, int tdmr_num) } } +/* + * Create TDMRs to cover all RAM entries in e820_table. The created + * TDMRs are saved to @tdmr_array and @tdmr_num is set to the actual + * number of TDMRs. All entries in @tdmr_array must be initially NULL. + */ +static int create_tdmrs(struct tdmr_info **tdmr_array, int *tdmr_num) +{ + struct tdmr_info *tdmr; + u64 start, end; + int i, tdmr_idx; + int ret = 0; + + tdmr_idx = 0; + tdmr = alloc_tdmr(tdmr_array, 0); + if (!tdmr) + return -ENOMEM; + /* + * Loop over all RAM entries in e820 and create TDMRs to cover + * them. To keep it simple, always try to use one TDMR to cover + * one RAM entry. + */ + e820_for_each_mem(e820_table, i, start, end) { + start = TDMR_ALIGN_DOWN(start); + end = TDMR_ALIGN_UP(end); + + /* + * If the current TDMR's size hasn't been initialized, it + * is a new allocated TDMR to cover the new RAM entry. + * Otherwise the current TDMR already covers the previous + * RAM entry. In the latter case, check whether the + * current RAM entry has been fully or partially covered + * by the current TDMR, since TDMR is 1G aligned. + */ + if (tdmr->size) { + /* + * Loop to next RAM entry if the current entry + * is already fully covered by the current TDMR. + */ + if (end <= TDMR_END(tdmr)) + continue; + + /* + * If part of current RAM entry has already been + * covered by current TDMR, skip the already + * covered part. + */ + if (start < TDMR_END(tdmr)) + start = TDMR_END(tdmr); + + /* + * Create a new TDMR to cover the current RAM + * entry, or the remaining part of it. + */ + tdmr_idx++; + if (tdmr_idx >= tdx_sysinfo.max_tdmrs) { + ret = -E2BIG; + goto err; + } + tdmr = alloc_tdmr(tdmr_array, tdmr_idx); + if (!tdmr) { + ret = -ENOMEM; + goto err; + } + } + + tdmr->base = start; + tdmr->size = end - start; + } + + /* @tdmr_idx is always the index of last valid TDMR. */ + *tdmr_num = tdmr_idx + 1; + + return 0; +err: + /* + * Clean up already allocated TDMRs in case of error. @tdmr_idx + * indicates the last TDMR that wasn't created successfully, + * therefore only needs to free @tdmr_idx TDMRs. + */ + free_tdmrs(tdmr_array, tdmr_idx); + return ret; +} + static int construct_tdmrs(struct tdmr_info **tdmr_array, int *tdmr_num) { int ret; @@ -830,8 +963,13 @@ static int construct_tdmrs(struct tdmr_info **tdmr_array, int *tdmr_num) if (ret) goto err; + ret = create_tdmrs(tdmr_array, tdmr_num); + if (ret) + goto err; + /* Return -EFAULT until constructing TDMRs is done */ ret = -EFAULT; + free_tdmrs(tdmr_array, *tdmr_num); err: return ret; } -- 2.35.1