On 24/04/2024 12:52, mii wrote:
>
> On 2024/04/24 10:28, Yong Huang wrote:
>>
>>
>> On Tue, Apr 23, 2024 at 9:35 PM Peter Xu <pet...@redhat.com> wrote:
>>
>> On Tue, Apr 23, 2024 at 09:13:08AM +0000, Masato Imai wrote:
>> > When the KVM acceleration parameter is not set, executing
>> calc_dirty_rate
>> > with the -r or -b option results in a segmentation fault due to
>> accessing
>> > a null kvm_state pointer in the kvm_dirty_ring_enabled function.
>> > This commit adds a check for kvm_enabled to prevent segmentation
>> faults.
>> >
>> > Signed-off-by: Masato Imai <m...@sfc.wide.ad.jp>
>> > ---
>> > migration/dirtyrate.c | 7 +++++++
>> > 1 file changed, 7 insertions(+)
>> >
>> > diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> > index 1d2e85746f..2a7df52519 100644
>> > --- a/migration/dirtyrate.c
>> > +++ b/migration/dirtyrate.c
>> > @@ -799,6 +799,13 @@ void qmp_calc_dirty_rate(int64_t calc_time,
>> > * dirty ring mode only works when kvm dirty ring is enabled.
>> > * on the contrary, dirty bitmap mode is not.
>> > */
>> > + if (!kvm_enabled() &&
>> > + (mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING ||
>> > + mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP)) {
>> > + error_setg(errp, "mode %s requires kvm to be enabled.",
>> > + DirtyRateMeasureMode_str(mode));
>> > + return;
>> > + }
>>
>> Logically dirty bitmap should work with tcg. So the other option is to
>> let
>> kvm_dirty_ring_enabled() check kvm_state too and return false if
>> kvm_state==NULL?
>>
>>
>> Agree, better solution
>>
>>
>> > if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) &&
>> > !kvm_dirty_ring_enabled()) ||
>> > ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) &&
>> > --
>> > 2.34.1
>> >
>>
>> --
>> Peter Xu
>>
>>
>> Thanks,
>> Yong
>>
>>
>> --
>> Best regards
>
> Thank you for the review. I agree with that solution.
>
> Update will be like:
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 931f74256e..0f8499365d 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -2312,6 +2312,9 @@ bool kvm_vcpu_id_is_valid(int vcpu_id)
>
> bool kvm_dirty_ring_enabled(void)
> {
How about,
return kvm_state && vm_state->kvm_dirty_ring_size;
Thanks
Zhijian
> + if (kvm_state == NULL) {
> + return false;
> + }
> return kvm_state->kvm_dirty_ring_size ? true : false;
> }
>
