From: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com
[ Upstream commit c1ed1754f271f6b7acb1bfdc8cfb62220fbed423 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kvm/book3s_64_mmu_radix.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c index d4e532a63f08e..2f27faf24b2cb 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)