After commit 45c7e8af4a5e3f0bea4ac209 ("MIPS: Remove KVM_TE support") we get a NULL pointer dereference when creating a KVM guest:

[ 146.243409] Starting KVM with MIPS VZ extensions [ 149.849151] CPU 3 Unable to handle kernel paging request at virtual address 0000000000000300, epc == ffffffffc06356ec, ra == ffffffffc063568c [ 149.849177] Oops[#1]: [ 149.849182] CPU: 3 PID: 2265 Comm: qemu-system-mip Not tainted 6.4.0-rc3+ #1671 [ 149.849188] Hardware name: THTF CX TL630 Series/THTF-LS3A4000-7A1000-ML4A, BIOS KL4.1F.TF.D.166.201225.R 12/25/2020 [ 149.849192] $ 0 : 0000000000000000 000000007400cce0 0000000000400004 ffffffff8119c740 [ 149.849209] $ 4 : 000000007400cce1 000000007400cce1 0000000000000000 0000000000000000 [ 149.849221] $ 8 : 000000240058bb36 ffffffff81421ac0 0000000000000000 0000000000400dc0 [ 149.849233] $12 : 9800000102a07cc8 ffffffff80e40e38 0000000000000001 0000000000400dc0 [ 149.849245] $16 : 0000000000000000 9800000106cd0000 9800000106cd0000 9800000100cce000 [ 149.849257] $20 : ffffffffc0632b28 ffffffffc05b31b0 9800000100ccca00 0000000000400000 [ 149.849269] $24 : 9800000106cd09ce ffffffff802f69d0 [ 149.849281] $28 : 9800000102a04000 9800000102a07cd0 98000001106a8000 ffffffffc063568c [ 149.849293] Hi : 00000335b2111e66 [ 149.849295] Lo : 6668d90061ae0ae9 [ 149.849298] epc : ffffffffc06356ec kvm_vz_vcpu_setup+0xc4/0x328 [kvm] [ 149.849324] ra : ffffffffc063568c kvm_vz_vcpu_setup+0x64/0x328 [kvm] [ 149.849336] Status: 7400cce3 KX SX UX KERNEL EXL IE [ 149.849351] Cause : 1000000c (ExcCode 03) [ 149.849354] BadVA : 0000000000000300 [ 149.849357] PrId : 0014c004 (ICT Loongson-3) [ 149.849360] Modules linked in: kvm nfnetlink_queue nfnetlink_log nfnetlink fuse sha256_generic libsha256 cfg80211 rfkill binfmt_misc vfat fat snd_hda_codec_hdmi input_leds led_class snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_pcm snd_timer snd serio_raw xhci_pci radeon drm_suballoc_helper drm_display_helper xhci_hcd ip_tables x_tables [ 149.849432] Process qemu-system-mip (pid: 2265, threadinfo=00000000ae2982d2, task=0000000038e09ad4, tls=000000ffeba16030) [ 149.849439] Stack : 9800000000000003 9800000100ccca00 9800000100ccc000 ffffffffc062cef4 [ 149.849453] 9800000102a07d18 c89b63a7ab338e00 0000000000000000 ffffffff811a0000 [ 149.849465] 0000000000000000 9800000106cd0000 ffffffff80e59938 98000001106a8920 [ 149.849476] ffffffff80e57f30 ffffffffc062854c ffffffff811a0000 9800000102bf4240 [ 149.849488] ffffffffc05b0000 ffffffff80e3a798 000000ff78000000 000000ff78000010 [ 149.849500] 0000000000000255 98000001021f7de0 98000001023f0078 ffffffff81434000 [ 149.849511] 0000000000000000 0000000000000000 9800000102ae0000 980000025e92ae28 [ 149.849523] 0000000000000000 c89b63a7ab338e00 0000000000000001 ffffffff8119dce0 [ 149.849535] 000000ff78000010 ffffffff804f3d3c 9800000102a07eb0 0000000000000255 [ 149.849546] 0000000000000000 ffffffff8049460c 000000ff78000010 0000000000000255 [ 149.849558] ... [ 149.849565] Call Trace: [ 149.849567] [<ffffffffc06356ec>] kvm_vz_vcpu_setup+0xc4/0x328 [kvm] [ 149.849586] [<ffffffffc062cef4>] kvm_arch_vcpu_create+0x184/0x228 [kvm] [ 149.849605] [<ffffffffc062854c>] kvm_vm_ioctl+0x64c/0xf28 [kvm] [ 149.849623] [<ffffffff805209c0>] sys_ioctl+0xc8/0x118 [ 149.849631] [<ffffffff80219eb0>] syscall_common+0x34/0x58

The root cause is the deletion of kvm_mips_commpage_init() leaves vcpu ->arch.cop0 NULL. So fix it by making cop0 from a pointer to an embedded object.

Fixes: 45c7e8af4a5e3f0bea4ac209 ("MIPS: Remove KVM_TE support") Cc: stable@vger.kernel.org Reported-by: Yu Zhao yuzhao@google.com Suggested-by: Thomas Bogendoerfer tsbogend@alpha.franken.de Reviewed-by: Philippe Mathieu-Daudé philmd@linaro.org Signed-off-by: Huacai Chen chenhuacai@loongson.cn --- V2: Update commit message and add Reported-by/Reviewed-by.

arch/mips/include/asm/kvm_host.h | 6 +++--- arch/mips/kvm/emulate.c | 22 +++++++++++----------- arch/mips/kvm/mips.c | 16 ++++++++-------- arch/mips/kvm/trace.h | 8 ++++---- arch/mips/kvm/vz.c | 20 ++++++++++---------- 5 files changed, 36 insertions(+), 36 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index 957121a495f0..04cedf9f8811 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -317,7 +317,7 @@ struct kvm_vcpu_arch { unsigned int aux_inuse;

/* COP0 State */ - struct mips_coproc *cop0; + struct mips_coproc cop0;

/* Resume PC after MMIO completion */ unsigned long io_pc; @@ -698,7 +698,7 @@ static inline bool kvm_mips_guest_can_have_fpu(struct kvm_vcpu_arch *vcpu) static inline bool kvm_mips_guest_has_fpu(struct kvm_vcpu_arch *vcpu) { return kvm_mips_guest_can_have_fpu(vcpu) && - kvm_read_c0_guest_config1(vcpu->cop0) & MIPS_CONF1_FP; + kvm_read_c0_guest_config1(&vcpu->cop0) & MIPS_CONF1_FP; }

static inline bool kvm_mips_guest_can_have_msa(struct kvm_vcpu_arch *vcpu) @@ -710,7 +710,7 @@ static inline bool kvm_mips_guest_can_have_msa(struct kvm_vcpu_arch *vcpu) static inline bool kvm_mips_guest_has_msa(struct kvm_vcpu_arch *vcpu) { return kvm_mips_guest_can_have_msa(vcpu) && - kvm_read_c0_guest_config3(vcpu->cop0) & MIPS_CONF3_MSA; + kvm_read_c0_guest_config3(&vcpu->cop0) & MIPS_CONF3_MSA; }

struct kvm_mips_callbacks { diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c index edaec93a1a1f..e64372b8f66a 100644 --- a/arch/mips/kvm/emulate.c +++ b/arch/mips/kvm/emulate.c @@ -312,7 +312,7 @@ int kvm_get_badinstrp(u32 *opc, struct kvm_vcpu *vcpu, u32 *out) */ int kvm_mips_count_disabled(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0;

return (vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) || (kvm_read_c0_guest_cause(cop0) & CAUSEF_DC); @@ -384,7 +384,7 @@ static inline ktime_t kvm_mips_count_time(struct kvm_vcpu *vcpu) */ static u32 kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; ktime_t expires, threshold; u32 count, compare; int running; @@ -444,7 +444,7 @@ static u32 kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now) */ u32 kvm_mips_read_count(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0;

/* If count disabled just read static copy of count */ if (kvm_mips_count_disabled(vcpu)) @@ -502,7 +502,7 @@ ktime_t kvm_mips_freeze_hrtimer(struct kvm_vcpu *vcpu, u32 *count) static void kvm_mips_resume_hrtimer(struct kvm_vcpu *vcpu, ktime_t now, u32 count) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; u32 compare; u64 delta; ktime_t expire; @@ -603,7 +603,7 @@ int kvm_mips_restore_hrtimer(struct kvm_vcpu *vcpu, ktime_t before, */ void kvm_mips_write_count(struct kvm_vcpu *vcpu, u32 count) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; ktime_t now;

/* Calculate bias */ @@ -649,7 +649,7 @@ void kvm_mips_init_count(struct kvm_vcpu *vcpu, unsigned long count_hz) */ int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; int dc; ktime_t now; u32 count; @@ -696,7 +696,7 @@ int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz) */ void kvm_mips_write_compare(struct kvm_vcpu *vcpu, u32 compare, bool ack) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; int dc; u32 old_compare = kvm_read_c0_guest_compare(cop0); s32 delta = compare - old_compare; @@ -779,7 +779,7 @@ void kvm_mips_write_compare(struct kvm_vcpu *vcpu, u32 compare, bool ack) */ static ktime_t kvm_mips_count_disable(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; u32 count; ktime_t now;

@@ -806,7 +806,7 @@ static ktime_t kvm_mips_count_disable(struct kvm_vcpu *vcpu) */ void kvm_mips_count_disable_cause(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0;

kvm_set_c0_guest_cause(cop0, CAUSEF_DC); if (!(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC)) @@ -826,7 +826,7 @@ void kvm_mips_count_disable_cause(struct kvm_vcpu *vcpu) */ void kvm_mips_count_enable_cause(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; u32 count;

kvm_clear_c0_guest_cause(cop0, CAUSEF_DC); @@ -852,7 +852,7 @@ void kvm_mips_count_enable_cause(struct kvm_vcpu *vcpu) */ int kvm_mips_set_count_ctl(struct kvm_vcpu *vcpu, s64 count_ctl) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; s64 changed = count_ctl ^ vcpu->arch.count_ctl; s64 delta; ktime_t expire, now; diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 884be4ef99dc..aa5583a7b05b 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -649,7 +649,7 @@ static int kvm_mips_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices) static int kvm_mips_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; struct mips_fpu_struct *fpu = &vcpu->arch.fpu; int ret; s64 v; @@ -761,7 +761,7 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu, static int kvm_mips_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; struct mips_fpu_struct *fpu = &vcpu->arch.fpu; s64 v; s64 vs[2]; @@ -1086,7 +1086,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) { return kvm_mips_pending_timer(vcpu) || - kvm_read_c0_guest_cause(vcpu->arch.cop0) & C_TI; + kvm_read_c0_guest_cause(&vcpu->arch.cop0) & C_TI; }

int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu) @@ -1110,7 +1110,7 @@ int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu) kvm_debug("\thi: 0x%08lx\n", vcpu->arch.hi); kvm_debug("\tlo: 0x%08lx\n", vcpu->arch.lo);

- cop0 = vcpu->arch.cop0; + cop0 = &vcpu->arch.cop0; kvm_debug("\tStatus: 0x%08x, Cause: 0x%08x\n", kvm_read_c0_guest_status(cop0), kvm_read_c0_guest_cause(cop0)); @@ -1232,7 +1232,7 @@ static int __kvm_mips_handle_exit(struct kvm_vcpu *vcpu)

case EXCCODE_TLBS: kvm_debug("TLB ST fault: cause %#x, status %#x, PC: %p, BadVaddr: %#lx\n", - cause, kvm_read_c0_guest_status(vcpu->arch.cop0), opc, + cause, kvm_read_c0_guest_status(&vcpu->arch.cop0), opc, badvaddr);

++vcpu->stat.tlbmiss_st_exits; @@ -1304,7 +1304,7 @@ static int __kvm_mips_handle_exit(struct kvm_vcpu *vcpu) kvm_get_badinstr(opc, vcpu, &inst); kvm_err("Exception Code: %d, not yet handled, @ PC: %p, inst: 0x%08x BadVaddr: %#lx Status: %#x\n", exccode, opc, inst, badvaddr, - kvm_read_c0_guest_status(vcpu->arch.cop0)); + kvm_read_c0_guest_status(&vcpu->arch.cop0)); kvm_arch_vcpu_dump_regs(vcpu); run->exit_reason = KVM_EXIT_INTERNAL_ERROR; ret = RESUME_HOST; @@ -1377,7 +1377,7 @@ int noinstr kvm_mips_handle_exit(struct kvm_vcpu *vcpu) /* Enable FPU for guest and restore context */ void kvm_own_fpu(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; unsigned int sr, cfg5;

preempt_disable(); @@ -1421,7 +1421,7 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu) /* Enable MSA for guest and restore context */ void kvm_own_msa(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; unsigned int sr, cfg5;

preempt_disable(); diff --git a/arch/mips/kvm/trace.h b/arch/mips/kvm/trace.h index a8c7fd7bf6d2..136c3535a1cb 100644 --- a/arch/mips/kvm/trace.h +++ b/arch/mips/kvm/trace.h @@ -322,11 +322,11 @@ TRACE_EVENT_FN(kvm_guest_mode_change, ),

TP_fast_assign( - __entry->epc = kvm_read_c0_guest_epc(vcpu->arch.cop0); + __entry->epc = kvm_read_c0_guest_epc(&vcpu->arch.cop0); __entry->pc = vcpu->arch.pc; - __entry->badvaddr = kvm_read_c0_guest_badvaddr(vcpu->arch.cop0); - __entry->status = kvm_read_c0_guest_status(vcpu->arch.cop0); - __entry->cause = kvm_read_c0_guest_cause(vcpu->arch.cop0); + __entry->badvaddr = kvm_read_c0_guest_badvaddr(&vcpu->arch.cop0); + __entry->status = kvm_read_c0_guest_status(&vcpu->arch.cop0); + __entry->cause = kvm_read_c0_guest_cause(&vcpu->arch.cop0); ),

TP_printk("EPC: 0x%08lx PC: 0x%08lx Status: 0x%08x Cause: 0x%08x BadVAddr: 0x%08lx", diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c index 3d21cbfa7443..99d5a71e4300 100644 --- a/arch/mips/kvm/vz.c +++ b/arch/mips/kvm/vz.c @@ -422,7 +422,7 @@ static void _kvm_vz_restore_htimer(struct kvm_vcpu *vcpu, */ static void kvm_vz_restore_timer(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; u32 cause, compare;

compare = kvm_read_sw_gc0_compare(cop0); @@ -517,7 +517,7 @@ static void _kvm_vz_save_htimer(struct kvm_vcpu *vcpu, */ static void kvm_vz_save_timer(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; u32 gctl0, compare, cause;

gctl0 = read_c0_guestctl0(); @@ -863,7 +863,7 @@ static unsigned long mips_process_maar(unsigned int op, unsigned long val)

static void kvm_write_maari(struct kvm_vcpu *vcpu, unsigned long val) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0;

val &= MIPS_MAARI_INDEX; if (val == MIPS_MAARI_INDEX) @@ -876,7 +876,7 @@ static enum emulation_result kvm_vz_gpsi_cop0(union mips_instruction inst, u32 *opc, u32 cause, struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; enum emulation_result er = EMULATE_DONE; u32 rt, rd, sel; unsigned long curr_pc; @@ -1911,7 +1911,7 @@ static int kvm_vz_get_one_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg, s64 *v) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; unsigned int idx;

switch (reg->id) { @@ -2081,7 +2081,7 @@ static int kvm_vz_get_one_reg(struct kvm_vcpu *vcpu, case KVM_REG_MIPS_CP0_MAARI: if (!cpu_guest_has_maar || cpu_guest_has_dyn_maar) return -EINVAL; - *v = kvm_read_sw_gc0_maari(vcpu->arch.cop0); + *v = kvm_read_sw_gc0_maari(&vcpu->arch.cop0); break; #ifdef CONFIG_64BIT case KVM_REG_MIPS_CP0_XCONTEXT: @@ -2135,7 +2135,7 @@ static int kvm_vz_set_one_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg, s64 v) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; unsigned int idx; int ret = 0; unsigned int cur, change; @@ -2562,7 +2562,7 @@ static void kvm_vz_vcpu_load_tlb(struct kvm_vcpu *vcpu, int cpu)

static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; bool migrated, all;

/* @@ -2704,7 +2704,7 @@ static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

static int kvm_vz_vcpu_put(struct kvm_vcpu *vcpu, int cpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0;

if (current->flags & PF_VCPU) kvm_vz_vcpu_save_wired(vcpu); @@ -3076,7 +3076,7 @@ static void kvm_vz_vcpu_uninit(struct kvm_vcpu *vcpu)

static int kvm_vz_vcpu_setup(struct kvm_vcpu *vcpu) { - struct mips_coproc *cop0 = vcpu->arch.cop0; + struct mips_coproc *cop0 = &vcpu->arch.cop0; unsigned long count_hz = 100*1000*1000; /* default to 100 MHz */

/*