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MIPS: KVM: Fix NULL pointer dereference
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commit e4de2057698636c0ee709e545d19b169d2069fa3 upstream.

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[projectceladon#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: 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]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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@chenhuacai @gregkh
chenhuacai authored and gregkh committed Jul 23, 2023
1 parent fd89522 commit cd517f9
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Showing 5 changed files with 36 additions and 36 deletions.
6 changes: 3 additions & 3 deletions arch/mips/include/asm/kvm_host.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -318,7 +318,7 @@ 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;
Expand Down Expand Up @@ -699,7 +699,7 @@ 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)
Expand All @@ -711,7 +711,7 @@ 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 {
Expand Down
22 changes: 11 additions & 11 deletions arch/mips/kvm/emulate.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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))
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;

Expand All @@ -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))
Expand All @@ -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);
Expand All @@ -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;
Expand Down
16 changes: 8 additions & 8 deletions arch/mips/kvm/mips.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -652,7 +652,7 @@ 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;
Expand Down Expand Up @@ -764,7 +764,7 @@ 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];
Expand Down Expand Up @@ -1104,7 +1104,7 @@ 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)
Expand All @@ -1128,7 +1128,7 @@ 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));
Expand Down Expand Up @@ -1250,7 +1250,7 @@ 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;
Expand Down Expand Up @@ -1322,7 +1322,7 @@ 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;
Expand Down Expand Up @@ -1384,7 +1384,7 @@ int 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();
Expand Down Expand Up @@ -1428,7 +1428,7 @@ 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();
Expand Down
8 changes: 4 additions & 4 deletions arch/mips/kvm/trace.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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",
Expand Down
20 changes: 10 additions & 10 deletions arch/mips/kvm/vz.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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();
Expand Down Expand Up @@ -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)
Expand All @@ -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;
Expand Down Expand Up @@ -1905,7 +1905,7 @@ 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) {
Expand Down Expand Up @@ -2075,7 +2075,7 @@ 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:
Expand Down Expand Up @@ -2129,7 +2129,7 @@ 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;
Expand Down Expand Up @@ -2556,7 +2556,7 @@ 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;

/*
Expand Down Expand Up @@ -2698,7 +2698,7 @@ 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);
Expand Down Expand Up @@ -3070,7 +3070,7 @@ 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 */

/*
Expand Down

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