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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Liran Alon <liran.alon@oracle.com>
Cc: qemu-devel@nongnu.org, pbonzini@redhat.com, mtosatti@redhat.com,
	rth@twiddle.net, ehabkost@redhat.com, kvm@vger.kernel.org,
	jmattson@google.com, maran.wilson@oracle.com,
	Nikita Leshenko <nikita.leshchenko@oracle.com>
Subject: Re: [QEMU PATCH v3 7/9] KVM: i386: Add support for save and restore nested state
Date: Tue, 18 Jun 2019 16:48:17 +0100
Message-ID: <20190618154817.GI2850@work-vm> (raw)
In-Reply-To: <32C4B530-A135-475B-B6AF-9288D372920D@oracle.com>

* Liran Alon (liran.alon@oracle.com) wrote:
> 
> > On 18 Jun 2019, at 12:03, Dr. David Alan Gilbert <dgilbert@redhat.com> wrote:
> > 
> > * Liran Alon (liran.alon@oracle.com) wrote:
> >> 
> >> +static const VMStateDescription vmstate_vmx_vmcs12 = {
> >> +	.name = "cpu/kvm_nested_state/vmx/vmcs12",
> >> +	.version_id = 1,
> >> +	.minimum_version_id = 1,
> >> +	.needed = vmx_vmcs12_needed,
> >> +	.fields = (VMStateField[]) {
> >> +	    VMSTATE_UINT8_ARRAY(data.vmx[0].vmcs12,
> >> +	                        struct kvm_nested_state, 0x1000),
> > 
> > Where did that magic 0x1000 come from?
> 
> Currently, KVM folks (including myself), haven’t decided yet to expose vmcs12 struct layout to userspace but instead to still leave it opaque.
> The formal size of this size is VMCS12_SIZE (defined in kernel as 0x1000). I was wondering if we wish to expose VMCS12_SIZE constant to userspace or not.
> So currently I defined these __u8 arrays as 0x1000. But in case Paolo agrees to expose VMCS12_SIZE, we can use that instead.

Well if it's not defined it's bound to change at some state!
Also, do we need to clear it before we get it from the kernel - e.g.
is the kernel guaranteed to give us 0x1000 ?

Dave

> -Liran
> 
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-17 17:56 [QEMU PATCH v3 0/9]: KVM: i386: Add support for save and restore of " Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 1/9] KVM: Introduce kvm_arch_destroy_vcpu() Liran Alon
2019-06-18 22:15   ` [Qemu-devel] " Maran Wilson
2019-06-17 17:56 ` [QEMU PATCH v3 2/9] KVM: i386: Use symbolic constant for #DB/#BP exception constants Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 3/9] KVM: i386: Re-inject #DB to guest with updated DR6 Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 4/9] KVM: i386: Block migration for vCPUs exposed with nested virtualization Liran Alon
2019-06-18  8:44   ` Dr. David Alan Gilbert
2019-06-18 22:16   ` [Qemu-devel] " Maran Wilson
2019-06-17 17:56 ` [QEMU PATCH v3 5/9] linux-headers: i386: Modify struct kvm_nested_state to have explicit fields for data Liran Alon
2019-06-18 22:16   ` [Qemu-devel] " Maran Wilson
2019-06-17 17:56 ` [QEMU PATCH v3 6/9] vmstate: Add support for kernel integer types Liran Alon
2019-06-18  8:55   ` Dr. David Alan Gilbert
2019-06-18 15:36     ` Liran Alon
2019-06-18 15:42       ` Dr. David Alan Gilbert
2019-06-18 16:44         ` Paolo Bonzini
2019-06-17 17:56 ` [QEMU PATCH v3 7/9] KVM: i386: Add support for save and restore nested state Liran Alon
2019-06-18  9:03   ` Dr. David Alan Gilbert
2019-06-18 15:40     ` Liran Alon
2019-06-18 15:48       ` Dr. David Alan Gilbert [this message]
2019-06-18 15:50         ` Liran Alon
2019-06-18 16:16         ` Paolo Bonzini
2019-06-18 22:16   ` [Qemu-devel] " Maran Wilson
2019-06-17 17:56 ` [QEMU PATCH v3 8/9] KVM: i386: Add support for KVM_CAP_EXCEPTION_PAYLOAD Liran Alon
2019-06-18  9:07   ` Dr. David Alan Gilbert
2019-06-18 15:45     ` Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 9/9] KVM: i386: Remove VMX migration blocker Liran Alon
2019-06-18 22:17   ` [Qemu-devel] " Maran Wilson

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