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chenhuacai
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MIPS: KVM: Fix NULL pointer dereference
After commit 45c7e8a ("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 : 1000000 (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: 45c7e8a ("MIPS: Remove KVM_TE support") Cc: [email protected] Reported-by: Yu Zhao <[email protected]> Suggested-by: Thomas Bogendoerfer <[email protected]> Reviewed-by: Philippe Mathieu-Daudé <[email protected]> Signed-off-by: Huacai Chen <[email protected]> Signed-off-by: Thomas Bogendoerfer <[email protected]>
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‎arch/mips/include/asm/kvm_host.h‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -317,7 +317,7 @@ struct kvm_vcpu_arch {
317317
unsigned int aux_inuse;
318318

319319
/* COP0 State */
320-
struct mips_coproc *cop0;
320+
struct mips_coproc cop0;
321321

322322
/* Resume PC after MMIO completion */
323323
unsigned long io_pc;
@@ -698,7 +698,7 @@ static inline bool kvm_mips_guest_can_have_fpu(struct kvm_vcpu_arch *vcpu)
698698
static inline bool kvm_mips_guest_has_fpu(struct kvm_vcpu_arch *vcpu)
699699
{
700700
return kvm_mips_guest_can_have_fpu(vcpu) &&
701-
kvm_read_c0_guest_config1(vcpu->cop0) & MIPS_CONF1_FP;
701+
kvm_read_c0_guest_config1(&vcpu->cop0) & MIPS_CONF1_FP;
702702
}
703703

704704
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)
710710
static inline bool kvm_mips_guest_has_msa(struct kvm_vcpu_arch *vcpu)
711711
{
712712
return kvm_mips_guest_can_have_msa(vcpu) &&
713-
kvm_read_c0_guest_config3(vcpu->cop0) & MIPS_CONF3_MSA;
713+
kvm_read_c0_guest_config3(&vcpu->cop0) & MIPS_CONF3_MSA;
714714
}
715715

716716
struct kvm_mips_callbacks {

‎arch/mips/kvm/emulate.c‎

Lines changed: 11 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -312,7 +312,7 @@ int kvm_get_badinstrp(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
312312
*/
313313
int kvm_mips_count_disabled(struct kvm_vcpu *vcpu)
314314
{
315-
struct mips_coproc *cop0 = vcpu->arch.cop0;
315+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
316316

317317
return (vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) ||
318318
(kvm_read_c0_guest_cause(cop0) & CAUSEF_DC);
@@ -384,7 +384,7 @@ static inline ktime_t kvm_mips_count_time(struct kvm_vcpu *vcpu)
384384
*/
385385
static u32 kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now)
386386
{
387-
struct mips_coproc *cop0 = vcpu->arch.cop0;
387+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
388388
ktime_t expires, threshold;
389389
u32 count, compare;
390390
int running;
@@ -444,7 +444,7 @@ static u32 kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now)
444444
*/
445445
u32 kvm_mips_read_count(struct kvm_vcpu *vcpu)
446446
{
447-
struct mips_coproc *cop0 = vcpu->arch.cop0;
447+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
448448

449449
/* If count disabled just read static copy of count */
450450
if (kvm_mips_count_disabled(vcpu))
@@ -502,7 +502,7 @@ ktime_t kvm_mips_freeze_hrtimer(struct kvm_vcpu *vcpu, u32 *count)
502502
static void kvm_mips_resume_hrtimer(struct kvm_vcpu *vcpu,
503503
ktime_t now, u32 count)
504504
{
505-
struct mips_coproc *cop0 = vcpu->arch.cop0;
505+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
506506
u32 compare;
507507
u64 delta;
508508
ktime_t expire;
@@ -603,7 +603,7 @@ int kvm_mips_restore_hrtimer(struct kvm_vcpu *vcpu, ktime_t before,
603603
*/
604604
void kvm_mips_write_count(struct kvm_vcpu *vcpu, u32 count)
605605
{
606-
struct mips_coproc *cop0 = vcpu->arch.cop0;
606+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
607607
ktime_t now;
608608

609609
/* Calculate bias */
@@ -649,7 +649,7 @@ void kvm_mips_init_count(struct kvm_vcpu *vcpu, unsigned long count_hz)
649649
*/
650650
int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz)
651651
{
652-
struct mips_coproc *cop0 = vcpu->arch.cop0;
652+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
653653
int dc;
654654
ktime_t now;
655655
u32 count;
@@ -696,7 +696,7 @@ int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz)
696696
*/
697697
void kvm_mips_write_compare(struct kvm_vcpu *vcpu, u32 compare, bool ack)
698698
{
699-
struct mips_coproc *cop0 = vcpu->arch.cop0;
699+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
700700
int dc;
701701
u32 old_compare = kvm_read_c0_guest_compare(cop0);
702702
s32 delta = compare - old_compare;
@@ -779,7 +779,7 @@ void kvm_mips_write_compare(struct kvm_vcpu *vcpu, u32 compare, bool ack)
779779
*/
780780
static ktime_t kvm_mips_count_disable(struct kvm_vcpu *vcpu)
781781
{
782-
struct mips_coproc *cop0 = vcpu->arch.cop0;
782+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
783783
u32 count;
784784
ktime_t now;
785785

@@ -806,7 +806,7 @@ static ktime_t kvm_mips_count_disable(struct kvm_vcpu *vcpu)
806806
*/
807807
void kvm_mips_count_disable_cause(struct kvm_vcpu *vcpu)
808808
{
809-
struct mips_coproc *cop0 = vcpu->arch.cop0;
809+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
810810

811811
kvm_set_c0_guest_cause(cop0, CAUSEF_DC);
812812
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)
826826
*/
827827
void kvm_mips_count_enable_cause(struct kvm_vcpu *vcpu)
828828
{
829-
struct mips_coproc *cop0 = vcpu->arch.cop0;
829+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
830830
u32 count;
831831

832832
kvm_clear_c0_guest_cause(cop0, CAUSEF_DC);
@@ -852,7 +852,7 @@ void kvm_mips_count_enable_cause(struct kvm_vcpu *vcpu)
852852
*/
853853
int kvm_mips_set_count_ctl(struct kvm_vcpu *vcpu, s64 count_ctl)
854854
{
855-
struct mips_coproc *cop0 = vcpu->arch.cop0;
855+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
856856
s64 changed = count_ctl ^ vcpu->arch.count_ctl;
857857
s64 delta;
858858
ktime_t expire, now;

‎arch/mips/kvm/mips.c‎

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -649,7 +649,7 @@ static int kvm_mips_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices)
649649
static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
650650
const struct kvm_one_reg *reg)
651651
{
652-
struct mips_coproc *cop0 = vcpu->arch.cop0;
652+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
653653
struct mips_fpu_struct *fpu = &vcpu->arch.fpu;
654654
int ret;
655655
s64 v;
@@ -761,7 +761,7 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
761761
static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
762762
const struct kvm_one_reg *reg)
763763
{
764-
struct mips_coproc *cop0 = vcpu->arch.cop0;
764+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
765765
struct mips_fpu_struct *fpu = &vcpu->arch.fpu;
766766
s64 v;
767767
s64 vs[2];
@@ -1086,7 +1086,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
10861086
int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
10871087
{
10881088
return kvm_mips_pending_timer(vcpu) ||
1089-
kvm_read_c0_guest_cause(vcpu->arch.cop0) & C_TI;
1089+
kvm_read_c0_guest_cause(&vcpu->arch.cop0) & C_TI;
10901090
}
10911091

10921092
int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu)
@@ -1110,7 +1110,7 @@ int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu)
11101110
kvm_debug("\thi: 0x%08lx\n", vcpu->arch.hi);
11111111
kvm_debug("\tlo: 0x%08lx\n", vcpu->arch.lo);
11121112

1113-
cop0 = vcpu->arch.cop0;
1113+
cop0 = &vcpu->arch.cop0;
11141114
kvm_debug("\tStatus: 0x%08x, Cause: 0x%08x\n",
11151115
kvm_read_c0_guest_status(cop0),
11161116
kvm_read_c0_guest_cause(cop0));
@@ -1232,7 +1232,7 @@ static int __kvm_mips_handle_exit(struct kvm_vcpu *vcpu)
12321232

12331233
case EXCCODE_TLBS:
12341234
kvm_debug("TLB ST fault: cause %#x, status %#x, PC: %p, BadVaddr: %#lx\n",
1235-
cause, kvm_read_c0_guest_status(vcpu->arch.cop0), opc,
1235+
cause, kvm_read_c0_guest_status(&vcpu->arch.cop0), opc,
12361236
badvaddr);
12371237

12381238
++vcpu->stat.tlbmiss_st_exits;
@@ -1304,7 +1304,7 @@ static int __kvm_mips_handle_exit(struct kvm_vcpu *vcpu)
13041304
kvm_get_badinstr(opc, vcpu, &inst);
13051305
kvm_err("Exception Code: %d, not yet handled, @ PC: %p, inst: 0x%08x BadVaddr: %#lx Status: %#x\n",
13061306
exccode, opc, inst, badvaddr,
1307-
kvm_read_c0_guest_status(vcpu->arch.cop0));
1307+
kvm_read_c0_guest_status(&vcpu->arch.cop0));
13081308
kvm_arch_vcpu_dump_regs(vcpu);
13091309
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
13101310
ret = RESUME_HOST;
@@ -1377,7 +1377,7 @@ int noinstr kvm_mips_handle_exit(struct kvm_vcpu *vcpu)
13771377
/* Enable FPU for guest and restore context */
13781378
void kvm_own_fpu(struct kvm_vcpu *vcpu)
13791379
{
1380-
struct mips_coproc *cop0 = vcpu->arch.cop0;
1380+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
13811381
unsigned int sr, cfg5;
13821382

13831383
preempt_disable();
@@ -1421,7 +1421,7 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
14211421
/* Enable MSA for guest and restore context */
14221422
void kvm_own_msa(struct kvm_vcpu *vcpu)
14231423
{
1424-
struct mips_coproc *cop0 = vcpu->arch.cop0;
1424+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
14251425
unsigned int sr, cfg5;
14261426

14271427
preempt_disable();

‎arch/mips/kvm/trace.h‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -322,11 +322,11 @@ TRACE_EVENT_FN(kvm_guest_mode_change,
322322
),
323323

324324
TP_fast_assign(
325-
__entry->epc = kvm_read_c0_guest_epc(vcpu->arch.cop0);
325+
__entry->epc = kvm_read_c0_guest_epc(&vcpu->arch.cop0);
326326
__entry->pc = vcpu->arch.pc;
327-
__entry->badvaddr = kvm_read_c0_guest_badvaddr(vcpu->arch.cop0);
328-
__entry->status = kvm_read_c0_guest_status(vcpu->arch.cop0);
329-
__entry->cause = kvm_read_c0_guest_cause(vcpu->arch.cop0);
327+
__entry->badvaddr = kvm_read_c0_guest_badvaddr(&vcpu->arch.cop0);
328+
__entry->status = kvm_read_c0_guest_status(&vcpu->arch.cop0);
329+
__entry->cause = kvm_read_c0_guest_cause(&vcpu->arch.cop0);
330330
),
331331

332332
TP_printk("EPC: 0x%08lx PC: 0x%08lx Status: 0x%08x Cause: 0x%08x BadVAddr: 0x%08lx",

‎arch/mips/kvm/vz.c‎

Lines changed: 10 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -422,7 +422,7 @@ static void _kvm_vz_restore_htimer(struct kvm_vcpu *vcpu,
422422
*/
423423
static void kvm_vz_restore_timer(struct kvm_vcpu *vcpu)
424424
{
425-
struct mips_coproc *cop0 = vcpu->arch.cop0;
425+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
426426
u32 cause, compare;
427427

428428
compare = kvm_read_sw_gc0_compare(cop0);
@@ -517,7 +517,7 @@ static void _kvm_vz_save_htimer(struct kvm_vcpu *vcpu,
517517
*/
518518
static void kvm_vz_save_timer(struct kvm_vcpu *vcpu)
519519
{
520-
struct mips_coproc *cop0 = vcpu->arch.cop0;
520+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
521521
u32 gctl0, compare, cause;
522522

523523
gctl0 = read_c0_guestctl0();
@@ -863,7 +863,7 @@ static unsigned long mips_process_maar(unsigned int op, unsigned long val)
863863

864864
static void kvm_write_maari(struct kvm_vcpu *vcpu, unsigned long val)
865865
{
866-
struct mips_coproc *cop0 = vcpu->arch.cop0;
866+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
867867

868868
val &= MIPS_MAARI_INDEX;
869869
if (val == MIPS_MAARI_INDEX)
@@ -876,7 +876,7 @@ static enum emulation_result kvm_vz_gpsi_cop0(union mips_instruction inst,
876876
u32 *opc, u32 cause,
877877
struct kvm_vcpu *vcpu)
878878
{
879-
struct mips_coproc *cop0 = vcpu->arch.cop0;
879+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
880880
enum emulation_result er = EMULATE_DONE;
881881
u32 rt, rd, sel;
882882
unsigned long curr_pc;
@@ -1911,7 +1911,7 @@ static int kvm_vz_get_one_reg(struct kvm_vcpu *vcpu,
19111911
const struct kvm_one_reg *reg,
19121912
s64 *v)
19131913
{
1914-
struct mips_coproc *cop0 = vcpu->arch.cop0;
1914+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
19151915
unsigned int idx;
19161916

19171917
switch (reg->id) {
@@ -2081,7 +2081,7 @@ static int kvm_vz_get_one_reg(struct kvm_vcpu *vcpu,
20812081
case KVM_REG_MIPS_CP0_MAARI:
20822082
if (!cpu_guest_has_maar || cpu_guest_has_dyn_maar)
20832083
return -EINVAL;
2084-
*v = kvm_read_sw_gc0_maari(vcpu->arch.cop0);
2084+
*v = kvm_read_sw_gc0_maari(&vcpu->arch.cop0);
20852085
break;
20862086
#ifdef CONFIG_64BIT
20872087
case KVM_REG_MIPS_CP0_XCONTEXT:
@@ -2135,7 +2135,7 @@ static int kvm_vz_set_one_reg(struct kvm_vcpu *vcpu,
21352135
const struct kvm_one_reg *reg,
21362136
s64 v)
21372137
{
2138-
struct mips_coproc *cop0 = vcpu->arch.cop0;
2138+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
21392139
unsigned int idx;
21402140
int ret = 0;
21412141
unsigned int cur, change;
@@ -2562,7 +2562,7 @@ static void kvm_vz_vcpu_load_tlb(struct kvm_vcpu *vcpu, int cpu)
25622562

25632563
static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
25642564
{
2565-
struct mips_coproc *cop0 = vcpu->arch.cop0;
2565+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
25662566
bool migrated, all;
25672567

25682568
/*
@@ -2704,7 +2704,7 @@ static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
27042704

27052705
static int kvm_vz_vcpu_put(struct kvm_vcpu *vcpu, int cpu)
27062706
{
2707-
struct mips_coproc *cop0 = vcpu->arch.cop0;
2707+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
27082708

27092709
if (current->flags & PF_VCPU)
27102710
kvm_vz_vcpu_save_wired(vcpu);
@@ -3076,7 +3076,7 @@ static void kvm_vz_vcpu_uninit(struct kvm_vcpu *vcpu)
30763076

30773077
static int kvm_vz_vcpu_setup(struct kvm_vcpu *vcpu)
30783078
{
3079-
struct mips_coproc *cop0 = vcpu->arch.cop0;
3079+
struct mips_coproc *cop0 = &vcpu->arch.cop0;
30803080
unsigned long count_hz = 100*1000*1000; /* default to 100 MHz */
30813081

30823082
/*

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