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From: Andre Przywara <andre.przywara@arm.com>
To: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Gleb Natapov <gleb@kernel.org>
Cc: "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>
Subject: Reason for extra struct kvm_run parameter in MMIO handling?
Date: Fri, 06 Feb 2015 17:30:45 +0000	[thread overview]
Message-ID: <54D4FA45.1000103@arm.com> (raw)

Hi,

while reworking the ARM vGIC emulation layer to use the kvm_io_bus
framework, I wonder why the whole KVM MMIO handling always passes the
pointer to struct kvm_run along with the struct kvm_vcpu pointer.
As kvm_run is a member of kvm_vcpu, the vcpu alone should be sufficient,
right?
Also I see the very top of the call chain is effectively:
kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);

So is that just legacy code still lingering around from the dawn of time
and nobody dared to rework this or is there a particular reason for
doing so?

I am asking because I lack the kvm_run pointer in the MMIO handler, so I
just use vcpu->run and I wonder if there are potential issues in doing so.

Cheers,
Andre.

             reply	other threads:[~2015-02-06 17:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-06 17:30 Andre Przywara [this message]
2015-02-09 16:21 ` Reason for extra struct kvm_run parameter in MMIO handling? Radim Krčmář
2015-02-09 16:26   ` Paolo Bonzini
2015-02-09 17:22     ` Andre Przywara

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