forked from Minki/linux
f4093ee9d0
Userland passes an array of 64 SLB descriptors to KVM_SET_SREGS, some of which are valid (ie, SLB_ESID_V is set) and the rest are likely all-zeroes (with QEMU at least). Each of them is then passed to kvmppc_mmu_book3s_64_slbmte(), which assumes to find the SLB index in the 3 lower bits of its rb argument. When passed zeroed arguments, it happily overwrites the 0th SLB entry with zeroes. This is exactly what happens while doing live migration with QEMU when the destination pushes the incoming SLB descriptors to KVM PR. When reloading the SLBs at the next synchronization, QEMU first clears its SLB array and only restore valid ones, but the 0th one is now gone and we cannot access the corresponding memory anymore: (qemu) x/x $pc c0000000000b742c: Cannot access memory To avoid this, let's filter out non-valid SLB entries. While here, we also force a full SLB flush before installing new entries. Since SLB is for 64-bit only, we now build this path conditionally to avoid a build break on 32-bit, which doesn't define SLB_ESID_V. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> |
||
|---|---|---|
| .. | ||
| alpha | ||
| arc | ||
| arm | ||
| arm64 | ||
| blackfin | ||
| c6x | ||
| cris | ||
| frv | ||
| h8300 | ||
| hexagon | ||
| ia64 | ||
| m32r | ||
| m68k | ||
| metag | ||
| microblaze | ||
| mips | ||
| mn10300 | ||
| nios2 | ||
| openrisc | ||
| parisc | ||
| powerpc | ||
| s390 | ||
| score | ||
| sh | ||
| sparc | ||
| tile | ||
| um | ||
| unicore32 | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| Kconfig | ||