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From:   "Wang, Wei W" <wei.w.wang@intel.com>
To:     Janosch Frank <frankja@linux.ibm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "pbonzini@redhat.com" <pbonzini@redhat.com>,
        "Zeng, Guang" <guang.zeng@intel.com>,
        "Liu, Jing2" <jing2.liu@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        "seanjc@google.com" <seanjc@google.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "Zhong, Yang" <yang.zhong@intel.com>
Subject: RE: [PATCH] kvm: Move KVM_GET_XSAVE2 IOCTL definition at the end of
 kvm.h
Thread-Topic: [PATCH] kvm: Move KVM_GET_XSAVE2 IOCTL definition at the end of
 kvm.h
Thread-Index: AQHYFF2HAjhbV221DEecjLl79IeG66x5LLxg
Date:   Sat, 29 Jan 2022 01:35:13 +0000
Message-ID: <c3d33dc642834f1db0a51e97fcc7f455@intel.com>
References: <20220128154025.102666-1-frankja@linux.ibm.com>
In-Reply-To: <20220128154025.102666-1-frankja@linux.ibm.com>
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On Friday, January 28, 2022 11:40 PM, Janosch Frank wrote:
> This way we can more easily find the next free IOCTL number when adding
> new IOCTLs.

Yes, this is good, but sometimes the relevant code tend to be put together =
(e.g. ioctl for vm fd and ioctls for vcpu fds), so not necessary to force t=
hem to be put in the number order.
I think it would be better to record the last used number in the comment on=
 top, and new additions need to update it (similar to the case that we upda=
te the api doc):

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 9563d294f181..b7e5199ec47e 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -6,6 +6,9 @@
  * Userspace interface for /dev/kvm - kernel based virtual machine
  *
  * Note: you must update KVM_API_VERSION if you change this interface.
+ *
+ * Last used cap number: KVM_CAP_XSAVE2(208)
+ * Last used ioctl number: KVM_HAS_DEVICE_ATTR(0xe3)
  */

 #include <linux/const.h>

Thanks,
Wei