cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

uaccess.c (1699B)

      1/* User memory access */
      2#include "qemu/osdep.h"
      3#include "qemu/cutils.h"
      4
      5#include "qemu.h"
      6
      7/* copy_from_user() and copy_to_user() are usually used to copy data
      8 * buffers between the target and host.  These internally perform
      9 * locking/unlocking of the memory.
     10 */
     11abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len)
     12{
     13    abi_long ret = 0;
     14    void *ghptr;
     15
     16    if ((ghptr = lock_user(VERIFY_READ, gaddr, len, 1))) {
     17        memcpy(hptr, ghptr, len);
     18        unlock_user(ghptr, gaddr, 0);
     19    } else
     20        ret = -TARGET_EFAULT;
     21
     22    return ret;
     23}
     24
     25
     26abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
     27{
     28    abi_long ret = 0;
     29    void *ghptr;
     30
     31    if ((ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0))) {
     32        memcpy(ghptr, hptr, len);
     33        unlock_user(ghptr, gaddr, len);
     34    } else
     35        ret = -TARGET_EFAULT;
     36
     37    return ret;
     38}
     39
     40/* Return the length of a string in target memory or -TARGET_EFAULT if
     41   access error  */
     42abi_long target_strlen(abi_ulong guest_addr1)
     43{
     44    uint8_t *ptr;
     45    abi_ulong guest_addr;
     46    int max_len, len;
     47
     48    guest_addr = guest_addr1;
     49    for (;;) {
     50        max_len = TARGET_PAGE_SIZE - (guest_addr & ~TARGET_PAGE_MASK);
     51        ptr = lock_user(VERIFY_READ, guest_addr, max_len, 1);
     52        if (!ptr)
     53            return -TARGET_EFAULT;
     54        len = qemu_strnlen((const char *)ptr, max_len);
     55        unlock_user(ptr, guest_addr, 0);
     56        guest_addr += len;
     57        /* we don't allow wrapping or integer overflow */
     58        if (guest_addr == 0 ||
     59            (guest_addr - guest_addr1) > 0x7fffffff)
     60            return -TARGET_EFAULT;
     61        if (len != max_len)
     62            break;
     63    }
     64    return guest_addr - guest_addr1;
     65}