[PATCH umr] Add initial AI VM decoding

Tom St Denis tom.stdenis at amd.com
Thu Apr 6 17:52:35 UTC 2017


Tested with VMID0 decodings just fine.  Haven't tried VMID1-15 yet.

Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
---
 src/lib/read_vram.c | 180 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 176 insertions(+), 4 deletions(-)

diff --git a/src/lib/read_vram.c b/src/lib/read_vram.c
index e2087a252c10..4c74f4521857 100644
--- a/src/lib/read_vram.c
+++ b/src/lib/read_vram.c
@@ -77,7 +77,6 @@ static int umr_read_sram(uint64_t address, uint32_t size, void *dst)
 	return -1;
 }
 
-
 static int umr_read_vram_vi(struct umr_asic *asic, uint32_t vmid, uint64_t address, uint32_t size, void *dst)
 {
 	uint64_t start_addr, page_table_start_addr, page_table_base_addr,
@@ -144,7 +143,7 @@ static int umr_read_vram_vi(struct umr_asic *asic, uint32_t vmid, uint64_t addre
 		if (page_table_depth == 1) {
 			// decode addr into pte and pde selectors...
 			pde_idx = (address >> (12 + 9 + page_table_size)) & ((1ULL << (40 - 12 - 9 - page_table_size)) - 1);
-			pte_idx = (address >> 12) & ((1ULL << (9 + page_table_size)) - 1);
+			pte_idx = (address >> (12 + page_table_size - 4)) & ((1ULL << (9 + page_table_size)) - 1);
 
 			// read PDE entry
 			umr_read_vram(asic, 0xFFFF, page_table_base_addr + pde_idx * 8, 8, &pde_entry);
@@ -210,6 +209,172 @@ static int umr_read_vram_vi(struct umr_asic *asic, uint32_t vmid, uint64_t addre
 	return 0;
 }
 
+static int umr_read_vram_ai(struct umr_asic *asic, uint32_t vmid, uint64_t address, uint32_t size, void *dst)
+{
+	uint64_t start_addr, page_table_start_addr, page_table_base_addr,
+		 page_table_size, pte_idx, pde_idx, pte_entry, pde_entry,
+		 pde_address;
+	uint32_t chunk_size, tmp;
+	int page_table_depth, first;
+	struct {
+		uint64_t
+			frag_size,
+			pte_base_addr,
+			valid;
+	} pde_fields;
+	struct {
+		uint64_t
+			page_base_addr,
+			fragment,
+			system,
+			valid;
+	} pte_fields;
+	char buf[64];
+	unsigned char *pdst = dst;
+
+	/*
+	 * PTE format on VI:
+	 * 63:40 reserved
+	 * 39:12 4k physical page base address
+	 * 11:7 fragment
+	 * 6 write
+	 * 5 read
+	 * 4 exe
+	 * 3 reserved
+	 * 2 snooped
+	 * 1 system
+	 * 0 valid
+	 *
+	 * PDE format on VI:
+	 * 63:59 block fragment size
+	 * 58:40 reserved
+	 * 39:1 physical base address of PTE
+	 * bits 5:1 must be 0.
+	 * 0 valid
+	 */
+
+	// read vm registers
+	sprintf(buf, "mmVM_CONTEXT%d_PAGE_TABLE_START_ADDR_LO32", (int)vmid);
+		page_table_start_addr = (uint64_t)umr_read_reg_by_name(asic, buf) << 12;
+	sprintf(buf, "mmVM_CONTEXT%d_PAGE_TABLE_START_ADDR_HI32", (int)vmid);
+		page_table_start_addr |= (uint64_t)umr_read_reg_by_name(asic, buf) << 44;
+
+	sprintf(buf, "mmVM_CONTEXT%d_CNTL", (int)vmid);
+		tmp = umr_read_reg_by_name(asic, buf);
+		page_table_depth      = umr_bitslice_reg_by_name(asic, buf, "PAGE_TABLE_DEPTH", tmp);
+		page_table_size       = umr_bitslice_reg_by_name(asic, buf, "PAGE_TABLE_BLOCK_SIZE", tmp);
+
+	sprintf(buf, "mmVM_CONTEXT%d_PAGE_TABLE_BASE_ADDR_LO32", (int)vmid);
+		page_table_base_addr  = (uint64_t)umr_read_reg_by_name(asic, buf) << 0;
+	sprintf(buf, "mmVM_CONTEXT%d_PAGE_TABLE_BASE_ADDR_HI32", (int)vmid);
+		page_table_base_addr  |= (uint64_t)umr_read_reg_by_name(asic, buf) << 32;
+
+	DEBUG("VIRT_ADDR = %08llx\n", (unsigned long long)address);
+	DEBUG("PAGE_START_ADDR = %08llx\n", (unsigned long long)page_table_start_addr);
+	DEBUG("BASE_ADDR = 0x%08llx\n", (unsigned long long)page_table_base_addr);
+	DEBUG("BASE_SIZE = %lu\n", page_table_size);
+	DEBUG("PAGE_TABLE_DEPTH = %d\n", page_table_depth);
+
+	address -= page_table_start_addr;
+
+	// AI+ allows 0=default (4KB) whereas VI requires it to be explictly set to >=4
+	page_table_size = page_table_size ? page_table_size : 4;
+
+	first = 1;
+	while (size) {
+		if (page_table_depth >= 1) {
+			// page_table_base_addr is not a PDE entry in this config so shift it out (it's a page address)
+			page_table_base_addr <<= 12;
+			pte_idx = (address >> (12 + page_table_size - 4)) & ((1ULL << (9 + page_table_size)) - 1);
+
+			// AI+ supports more than 1 level of PDEs so we iterate for all of the depths
+			pde_address = address;
+			while (page_table_depth) {
+				// decode addr into pte and pde selectors...
+				pde_idx = (pde_address >> (page_table_depth*9 + (12 + page_table_size - 4)));
+
+				// don't mask the first PDE idx
+				if (!first)
+					pde_idx &= (1ULL << 9) - 1;
+				first = 0;
+
+				// read PDE entry
+				umr_read_vram(asic, 0xFFFF, page_table_base_addr + pde_idx * 8, 8, &pde_entry);
+
+				// decode PDE values
+				pde_fields.frag_size     = (pde_entry >> 59) & 0x1F;
+				pde_fields.pte_base_addr = pde_entry & 0xFFFFFFFFF000ULL;
+				pde_fields.valid         = pde_entry & 1;
+				DEBUG("pde_idx=%llx, frag_size=%u, pte_base_addr=0x%llx, valid=%d\n", (unsigned long long)pde_idx, (unsigned)pde_fields.frag_size, (unsigned long long)pde_fields.pte_base_addr, (int)pde_fields.valid);
+
+				// for the next round the address we're decoding is the phys address in the currently decoded PDE
+				--page_table_depth;
+				pde_address = pde_fields.pte_base_addr;
+			}
+
+			// now read PTE entry for this page
+			umr_read_vram(asic, 0xFFFF, pde_fields.pte_base_addr + pte_idx*8, 8, &pte_entry);
+
+			// decode PTE values
+			pte_fields.page_base_addr = pte_entry & 0xFFFFFFFFF000ULL;
+			pte_fields.fragment       = (pte_entry >> 7)  & 0x1F;
+			pte_fields.system         = (pte_entry >> 1) & 1;
+			pte_fields.valid          = pte_entry & 1;
+			DEBUG("pte_idx=%llx, page_base_addr=0x%llx, fragment=%u, system=%d, valid=%d\n", (unsigned long long)pte_idx, (unsigned long long)pte_fields.page_base_addr, (unsigned)pte_fields.fragment, (int)pte_fields.system, (int)pte_fields.valid);
+
+			// compute starting address
+			start_addr = pte_fields.page_base_addr + (address & 0xFFF);
+		} else {
+			// in AI+ the BASE_ADDR is treated like a PDE entry...
+			// decode PDE values
+			pde_idx = 0; // unused
+			pde_fields.frag_size     = (page_table_base_addr >> 59) & 0x1F;
+			pde_fields.pte_base_addr = page_table_base_addr & 0xFFFFFFFFF000ULL;
+			pde_fields.valid         = page_table_base_addr & 1;
+			DEBUG("pde_idx=%llx, frag_size=%u, pte_base_addr=0x%llx, valid=%d\n", (unsigned long long)pde_idx, (unsigned)pde_fields.frag_size, (unsigned long long)pde_fields.pte_base_addr, (int)pde_fields.valid);
+
+			// PTE addr = baseaddr[47:6] + (logical - start) >> fragsize)
+			pte_idx = (address >> (12 + pde_fields.frag_size));
+
+			umr_read_vram(asic, 0xFFFF, pde_fields.pte_base_addr + pte_idx * 8, 8, &pte_entry);
+
+			// decode PTE values
+			pte_fields.page_base_addr = pte_entry & 0xFFFFFFFF000ULL;
+			pte_fields.fragment       = (pte_entry >> 7)  & 0x1F;
+			pte_fields.system         = (pte_entry >> 1) & 1;
+			pte_fields.valid          = pte_entry & 1;
+			DEBUG("pte_idx=%llx, page_base_addr=0x%llx, fragment=%u, system=%d, valid=%d\n", (unsigned long long)pte_idx, (unsigned long long)pte_fields.page_base_addr, (unsigned)pte_fields.fragment, (int)pte_fields.system, (int)pte_fields.valid);
+
+			// compute starting address
+			start_addr = pte_fields.page_base_addr + (address & 0xFFF);
+		}
+
+		// read upto 4K from it
+		// TODO: Support page sizes >4KB
+		if (((start_addr & 0xFFF) + size) & ~0xFFF) {
+			chunk_size = 0x1000 - (start_addr & 0xFFF);
+		} else {
+			chunk_size = size;
+		}
+		DEBUG("Computed address we will read from: %s:%llx (reading: %lu bytes)\n", pte_fields.system ? "sys" : "vram", (unsigned long long)start_addr, (unsigned long)chunk_size);
+		if (pte_fields.system) {
+			if (umr_read_sram(start_addr, chunk_size, pdst) < 0) {
+				fprintf(stderr, "[ERROR] Cannot read system ram, perhaps CONFIG_STRICT_DEVMEM is set in your kernel config?\n");
+				fprintf(stderr, "[ERROR] Alternatively download and install /dev/fmem\n");
+				return -1;
+			}
+		} else {
+			if (umr_read_vram(asic, 0xFFFF, start_addr, chunk_size, pdst) < 0) {
+				fprintf(stderr, "[ERROR] Cannot read from VRAM\n");
+				return -1;
+			}
+		}
+		pdst += chunk_size;
+		size -= chunk_size;
+		address += chunk_size;
+	}
+	return 0;
+}
 
 int umr_read_vram(struct umr_asic *asic, uint32_t vmid, uint64_t address, uint32_t size, void *dst)
 {
@@ -234,8 +399,15 @@ int umr_read_vram(struct umr_asic *asic, uint32_t vmid, uint64_t address, uint32
 		return 0;
 	}
 
-	if (asic->family == FAMILY_VI)
-		return umr_read_vram_vi(asic, vmid, address, size, dst);
+	switch (asic->family) {
+		case FAMILY_VI:
+			return umr_read_vram_vi(asic, vmid, address, size, dst);
+		case FAMILY_AI:
+			return umr_read_vram_ai(asic, vmid, address, size, dst);
+		default:
+			fprintf(stderr, "[BUG] Unsupported ASIC family type for umr_read_vram()\n");
+			return -1;
+	}
 
 	return 0;
 }
-- 
2.12.0



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