diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-06-11 17:31:59 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-06-22 21:55:45 +1000 |
| commit | c1ed1754f271f6b7acb1bfdc8cfb62220fbed423 (patch) | |
| tree | c13c0370bf3ccb550d53a5409fa768037e12d702 /arch/powerpc/kvm | |
| parent | 7e4773f73dcfb92e7e33532162f722ec291e75a4 (diff) | |
powerpc/kvm/book3s64: Fix kernel crash with nested kvm & DEBUG_VIRTUAL
With CONFIG_DEBUG_VIRTUAL=y, __pa() checks for addr value and if it's
less than PAGE_OFFSET it leads to a BUG().
#define __pa(x)
({
VIRTUAL_BUG_ON((unsigned long)(x) < PAGE_OFFSET);
(unsigned long)(x) & 0x0fffffffffffffffUL;
})
kernel BUG at arch/powerpc/kvm/book3s_64_mmu_radix.c:43!
cpu 0x70: Vector: 700 (Program Check) at [c0000018a2187360]
pc: c000000000161b30: __kvmhv_copy_tofrom_guest_radix+0x130/0x1f0
lr: c000000000161d5c: kvmhv_copy_from_guest_radix+0x3c/0x80
...
kvmhv_copy_from_guest_radix+0x3c/0x80
kvmhv_load_from_eaddr+0x48/0xc0
kvmppc_ld+0x98/0x1e0
kvmppc_load_last_inst+0x50/0x90
kvmppc_hv_emulate_mmio+0x288/0x2b0
kvmppc_book3s_radix_page_fault+0xd8/0x2b0
kvmppc_book3s_hv_page_fault+0x37c/0x1050
kvmppc_vcpu_run_hv+0xbb8/0x1080
kvmppc_vcpu_run+0x34/0x50
kvm_arch_vcpu_ioctl_run+0x2fc/0x410
kvm_vcpu_ioctl+0x2b4/0x8f0
ksys_ioctl+0xf4/0x150
sys_ioctl+0x28/0x80
system_call_exception+0x104/0x1d0
system_call_common+0xe8/0x214
kvmhv_copy_tofrom_guest_radix() uses a NULL value for to/from to
indicate direction of copy.
Avoid calling __pa() if the value is NULL to avoid the BUG().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Massage change log a bit to mention CONFIG_DEBUG_VIRTUAL]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611120159.680284-1-aneesh.kumar@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kvm')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c index e738ea652192..6a73714759ba 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c @@ -40,7 +40,8 @@ unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid, /* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */ if (kvmhv_on_pseries()) return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr, - __pa(to), __pa(from), n); + (to != NULL) ? __pa(to): 0, + (from != NULL) ? __pa(from): 0, n); quadrant = 1; if (!pid) |