From 27ac7a95b69d70622f281c1b8d0300d38e5c541d Mon Sep 17 00:00:00 2001 From: Louis Burda Date: Mon, 30 Jan 2023 11:25:17 +0100 Subject: Added mainpfn guest utility to determine rough pfn for userspace code --- util/.gitignore | 2 +- util/mainpfn.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 52 insertions(+), 1 deletion(-) create mode 100644 util/mainpfn.c (limited to 'util') diff --git a/util/.gitignore b/util/.gitignore index ef5bc67..dba752f 100644 --- a/util/.gitignore +++ b/util/.gitignore @@ -1,3 +1,3 @@ debug -svme reset +mainpfn diff --git a/util/mainpfn.c b/util/mainpfn.c new file mode 100644 index 0000000..17c1b18 --- /dev/null +++ b/util/mainpfn.c @@ -0,0 +1,51 @@ +#include +#include +#include +#include +#include +#include + +struct pageinfo { + uint64_t pfn : 54; + unsigned int soft_dirty : 1; + unsigned int file_page : 1; + unsigned int swapped : 1; + unsigned int present : 1; +}; + +void +pagemap_get_entry(struct pageinfo *entry, int fd, uintptr_t vaddr) +{ + uint64_t data; + size_t offset; + + offset = (vaddr / sysconf(_SC_PAGE_SIZE)) * 8; + if (pread(fd, (void *) &data, 8, offset) != 8) + err(1, "pread"); + + entry->pfn = data & ((1ULL << 54) - 1); + entry->soft_dirty = (data >> 54) & 1; + entry->file_page = (data >> 61) & 1; + entry->swapped = (data >> 62) & 1; + entry->present = (data >> 63) & 1; +} + +int +main(int argc, const char **argv) +{ + char filepath[256]; + struct pageinfo info; + pid_t pid; + int fd; + + pid = getpid(); + snprintf(filepath, sizeof(filepath), "/proc/%u/pagemap", pid); + + fd = open(filepath, O_RDONLY); + if (!fd) err(1, "open"); + + pagemap_get_entry(&info, fd, (uintptr_t) main); + printf("PFN: %08lx\n", info.pfn); + + close(fd); +} -- cgit v1.2.3-71-gd317