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From: Peter Xu <peterx@redhat.com>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Michael Tokarev <mjt@tls.msk.ru>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	"Michael S . Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH RFC 1/9] KVM: Fixup kvm_log_clear_one_slot() ioctl return check
Date: Wed, 25 Mar 2020 13:43:02 -0400
Message-ID: <20200325174302.GH354390@xz-x1> (raw)
In-Reply-To: <20200205141749.378044-2-peterx@redhat.com>

On Wed, Feb 05, 2020 at 09:17:41AM -0500, Peter Xu wrote:
> kvm_vm_ioctl() handles the errno trick already for ioctl() on
> returning -1 for errors.  Fix this.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  accel/kvm/kvm-all.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index c111312dfd..4be3cd2352 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -688,14 +688,13 @@ static int kvm_log_clear_one_slot(KVMSlot *mem, int as_id, uint64_t start,
>      d.num_pages = bmap_npages;
>      d.slot = mem->slot | (as_id << 16);
>  
> -    if (kvm_vm_ioctl(s, KVM_CLEAR_DIRTY_LOG, &d) == -1) {
> -        ret = -errno;
> +    ret = kvm_vm_ioctl(s, KVM_CLEAR_DIRTY_LOG, &d);

Dave raised a question offlist when comparing with KVM_GET_DIRTY_LOG,
regarding 50212d6346 ("Revert "fix return check for KVM_GET_DIRTY_LOG
ioctl"", 2014-04-14) where we wanted to allow KVM_GET_DIRTY_LOG to
fail for some cases.  I didn't find any context of that, and from the
first glance I don't understand why and when we'll get -ENOENT during
sync dirty log (we should have BQL held, so I don't know why a memslot
can be gone underneath).  Anyone knows more?

CCing Peter Maydell and Michael Tokarev too.

> +    if (ret) {
>          error_report("%s: KVM_CLEAR_DIRTY_LOG failed, slot=%d, "
>                       "start=0x%"PRIx64", size=0x%"PRIx32", errno=%d",
>                       __func__, d.slot, (uint64_t)d.first_page,
>                       (uint32_t)d.num_pages, ret);
>      } else {
> -        ret = 0;
>          trace_kvm_clear_dirty_log(d.slot, d.first_page, d.num_pages);
>      }
>  
> -- 
> 2.24.1
> 

-- 
Peter Xu



  parent reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-05 14:17 [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) Peter Xu
2020-02-05 14:17 ` [PATCH RFC 1/9] KVM: Fixup kvm_log_clear_one_slot() ioctl return check Peter Xu
2020-03-25 16:34   ` Dr. David Alan Gilbert
2020-03-25 17:43   ` Peter Xu [this message]
2020-02-05 14:17 ` [PATCH RFC 2/9] linux-headers: Update Peter Xu
2020-02-05 14:17 ` [PATCH RFC 3/9] memory: Introduce log_sync_global() to memory listener Peter Xu
2020-03-25 16:52   ` Dr. David Alan Gilbert
2020-03-25 17:02     ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 4/9] KVM: Create the KVMSlot dirty bitmap on flag changes Peter Xu
2020-03-25 17:44   ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 5/9] KVM: Provide helper to get kvm dirty log Peter Xu
2020-03-25 17:52   ` Dr. David Alan Gilbert
2020-03-25 18:15     ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 6/9] KVM: Provide helper to sync dirty bitmap from slot to ramblock Peter Xu
2020-03-25 18:47   ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 7/9] KVM: Cache kvm slot dirty bitmap size Peter Xu
2020-03-25 18:49   ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 8/9] KVM: Add dirty-ring-size property Peter Xu
2020-03-25 20:00   ` Dr. David Alan Gilbert
2020-03-25 20:42     ` Peter Xu
2020-03-26 13:41       ` Dr. David Alan Gilbert
2020-03-26 16:03         ` Peter Xu
2020-03-25 20:14   ` Dr. David Alan Gilbert
2020-03-25 20:48     ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 9/9] KVM: Dirty ring support Peter Xu
2020-03-25 20:41   ` Dr. David Alan Gilbert
2020-03-25 21:32     ` Peter Xu
2020-03-26 14:14       ` Dr. David Alan Gilbert
2020-03-26 16:10         ` Peter Xu
2020-02-05 14:51 ` [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) no-reply
2020-03-03 17:32 ` Peter Xu

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