WinDBG中!vad扩展的Start与End列含义咨询

Let me break down what those Start and End values mean—they’re key to mapping VAD entries to actual virtual address ranges, which is critical for your virtual-to-physical address conversion work.

First, a quick context check: VADs (Virtual Address Descriptors) are the Windows memory manager’s core structure for tracking chunks of a process’s virtual address space. Each !vad entry represents a contiguous block of virtual memory with uniform attributes (like the EXECUTE_WRITECOPY flag in your example).

What Start and End Actually Mean #

The Start and End columns display the page numbers of the virtual memory pages covered by this VAD. By default, Windows uses 4KB memory pages (unless large pages are explicitly enabled), so each page number corresponds to a 4KB block of virtual address space.

To convert these page numbers to usable virtual addresses:

• Take the Start value, shift it left by 12 bits (or multiply by 0x1000, which equals 4096) to get the first valid address of the region.
• For the End value, shift it left by 12 bits, then add 0xFFF (the maximum offset within a 4KB page) to get the last valid address in the region.

Applying This to Your Example #

Looking at your !vad output:

kd> !vad 824bc2f8
VAD     level      start      end    commit
82741bf8 (   1)    78000     78045        8 Mapped Exe EXECUTE_WRITECOPY...

• Start = 0x78000 (all values in !vad are hexadecimal by default) translates to a starting virtual address of 0x78000 * 0x1000 = 0x78000000.
• End = 0x78045 translates to an ending virtual address of 0x78045 * 0x1000 + 0xFFF = 0x78045FFF.

This means the VAD manages the virtual address range from 0x78000000 to 0x78045FFF. The commit value of 8 tells you 8 of those pages (32KB total) have been committed to physical memory or the page file so far—since this is a mapped EXE, Windows uses demand paging, so only the pages that have been accessed get committed upfront.

内容的提问来源于stack exchange，提问作者user5454875