From: Frederik Deweerdt <frederik.deweerdt@xprog.eu>
To: Glauber Costa <glommer@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, avi@redhat.com
Subject: Re: [PATCH] v3: allow userspace to adjust kvmclock offset
Date: Tue, 13 Oct 2009 21:11:37 +0000 [thread overview]
Message-ID: <20091013211137.GB31282@gambetta> (raw)
In-Reply-To: <1255467305-14748-1-git-send-email-glommer@redhat.com>
On Tue, Oct 13, 2009 at 04:55:05PM -0400, Glauber Costa wrote:
> + case KVM_SET_CLOCK: {
> + struct timespec now;
> + struct kvm_clock_data user_ns;
> + u64 now_ns;
> + long delta;
^^^^
Should'nt that read s64? I guess such a large value won't happen in
practice, but the 32bits case would truncate the value differently in
the substraction below.
Regards,
Frederik
> +
> + r = -EFAULT;
> + if (copy_from_user(&user_ns, argp, sizeof(user_ns)))
> + goto out;
> +
> + r = 0;
> + ktime_get_ts(&now);
> + now_ns = timespec_to_ns(&now);
> + delta = user_ns.clock - now_ns;
> + kvm->arch.kvmclock_offset = delta;
> + break;
> + }
> + case KVM_GET_CLOCK: {
> + struct timespec now;
> + struct kvm_clock_data user_ns;
> + u64 now_ns;
> +
> + ktime_get_ts(&now);
> + now_ns = timespec_to_ns(&now);
> + user_ns.clock = kvm->arch.kvmclock_offset + now_ns;
> +
> + if (copy_to_user(argp, &user_ns, sizeof(user_ns)))
> + r = -EFAULT;
> +
> + break;
> + }
> +
> default:
> ;
> }
> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
> index f8f8900..ad0ecbc 100644
> --- a/include/linux/kvm.h
> +++ b/include/linux/kvm.h
> @@ -497,6 +497,11 @@ struct kvm_irqfd {
> __u8 pad[20];
> };
>
> +struct kvm_clock_data {
> + __u64 clock;
> + __u64 pad[2];
> +};
> +
> /*
> * ioctls for VM fds
> */
> @@ -546,6 +551,8 @@ struct kvm_irqfd {
> #define KVM_CREATE_PIT2 _IOW(KVMIO, 0x77, struct kvm_pit_config)
> #define KVM_SET_BOOT_CPU_ID _IO(KVMIO, 0x78)
> #define KVM_IOEVENTFD _IOW(KVMIO, 0x79, struct kvm_ioeventfd)
> +#define KVM_SET_CLOCK _IOW(KVMIO, 0x7a, struct kvm_clock_data)
> +#define KVM_GET_CLOCK _IOW(KVMIO, 0x7b, struct kvm_clock_data)
>
> /*
> * ioctls for vcpu fds
> --
> 1.6.2.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
prev parent reply other threads:[~2009-10-13 21:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-13 20:55 [PATCH] v3: allow userspace to adjust kvmclock offset Glauber Costa
2009-10-13 21:11 ` Frederik Deweerdt [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20091013211137.GB31282@gambetta \
--to=frederik.deweerdt@xprog.eu \
--cc=avi@redhat.com \
--cc=glommer@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox