From: Cédric Le Goater clg@kaod.org
commit 75b49620267c700f0a07fec7f27f69852db70e46 upstream.
When accessing the ESB page of a source interrupt, the fault handler will retrieve the page address from the XIVE interrupt 'xive_irq_data' structure. If the associated KVM XIVE interrupt is not valid, that is not allocated at the HW level for some reason, the fault handler will dereference a NULL pointer leading to the oops below :
WARNING: CPU: 40 PID: 59101 at arch/powerpc/kvm/book3s_xive_native.c:259 xive_native_esb_fault+0xe4/0x240 [kvm] CPU: 40 PID: 59101 Comm: qemu-system-ppc Kdump: loaded Tainted: G W --------- - - 4.18.0-240.el8.ppc64le #1 NIP: c00800000e949fac LR: c00000000044b164 CTR: c00800000e949ec8 REGS: c000001f69617840 TRAP: 0700 Tainted: G W --------- - - (4.18.0-240.el8.ppc64le) MSR: 9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 44044282 XER: 00000000 CFAR: c00000000044b160 IRQMASK: 0 GPR00: c00000000044b164 c000001f69617ac0 c00800000e96e000 c000001f69617c10 GPR04: 05faa2b21e000080 0000000000000000 0000000000000005 ffffffffffffffff GPR08: 0000000000000000 0000000000000001 0000000000000000 0000000000000001 GPR12: c00800000e949ec8 c000001ffffd3400 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 c000001f5c065160 c000000001c76f90 GPR24: c000001f06f20000 c000001f5c065100 0000000000000008 c000001f0eb98c78 GPR28: c000001dcab40000 c000001dcab403d8 c000001f69617c10 0000000000000011 NIP [c00800000e949fac] xive_native_esb_fault+0xe4/0x240 [kvm] LR [c00000000044b164] __do_fault+0x64/0x220 Call Trace: [c000001f69617ac0] [0000000137a5dc20] 0x137a5dc20 (unreliable) [c000001f69617b50] [c00000000044b164] __do_fault+0x64/0x220 [c000001f69617b90] [c000000000453838] do_fault+0x218/0x930 [c000001f69617bf0] [c000000000456f50] __handle_mm_fault+0x350/0xdf0 [c000001f69617cd0] [c000000000457b1c] handle_mm_fault+0x12c/0x310 [c000001f69617d10] [c00000000007ef44] __do_page_fault+0x264/0xbb0 [c000001f69617df0] [c00000000007f8c8] do_page_fault+0x38/0xd0 [c000001f69617e30] [c00000000000a714] handle_page_fault+0x18/0x38 Instruction dump: 40c2fff0 7c2004ac 2fa90000 409e0118 73e90001 41820080 e8bd0008 7c2004ac 7ca90074 39400000 915c0000 7929d182 <0b090000> 2fa50000 419e0080 e89e0018 ---[ end trace 66c6ff034c53f64f ]--- xive-kvm: xive_native_esb_fault: accessing invalid ESB page for source 8 !
Fix that by checking the validity of the KVM XIVE interrupt structure.
Fixes: 6520ca64cde7 ("KVM: PPC: Book3S HV: XIVE: Add a mapping for the source ESB pages") Cc: stable@vger.kernel.org # v5.2+ Reported-by: Greg Kurz groug@kaod.org Signed-off-by: Cédric Le Goater clg@kaod.org Tested-by: Greg Kurz groug@kaod.org Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20201105134713.656160-1-clg@kaod.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/kvm/book3s_xive_native.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/arch/powerpc/kvm/book3s_xive_native.c +++ b/arch/powerpc/kvm/book3s_xive_native.c @@ -252,6 +252,13 @@ static vm_fault_t xive_native_esb_fault( }
state = &sb->irq_state[src]; + + /* Some sanity checking */ + if (!state->valid) { + pr_devel("%s: source %lx invalid !\n", __func__, irq); + return VM_FAULT_SIGBUS; + } + kvmppc_xive_select_irq(state, &hw_num, &xd);
arch_spin_lock(&sb->lock);