From: "Sebastian Schütte" <dracon@ewetel.net>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: KVM list <kvm@vger.kernel.org>
Subject: Re: [Bug 103321] New: NPT page attribute support causes extreme slowdown
Date: Wed, 2 Sep 2015 21:01:25 +0200 [thread overview]
Message-ID: <55E74785.2060701@ewetel.net> (raw)
In-Reply-To: <55DA8054.7080900@redhat.com>
I inserted some printk() lines into init_vmcb() around the call of svm_set_guest_pat() to print out the g_pat value as well as svm->vcpu.vcpu_id and noticed that something was off:
Initially, the PATs of all VCPUs are set to 0x0606060606060606. However, after attaching some devices (vfio-pci enabling device and vfio_ecap_init lines are being printed) init_vmcb() is only called again for vcpu_id > 0. Unless g_pat is changed somewhere else, VCPU #0 remains set to 0x0606060606060606 (according to comments in svm_set_guest_pat() this is bad for assigned devices) while all other VCPUs use 0x0007040600070406.
I'd guess that could explain the slowdown.
next prev parent reply other threads:[~2015-09-02 19:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-22 22:16 [Bug 103321] New: NPT page attribute support causes extreme slowdown bugzilla-daemon
2015-08-22 22:16 ` [Bug 103321] " bugzilla-daemon
2015-08-22 22:17 ` bugzilla-daemon
[not found] ` <55D90002.10703@redhat.com>
[not found] ` <55DA16BB.4020004@ewetel.net>
2015-08-24 2:24 ` [Bug 103321] New: " Paolo Bonzini
2015-08-24 22:55 ` Sebastian Schütte
2015-09-02 19:01 ` Sebastian Schütte [this message]
2015-09-15 16:32 ` Paolo Bonzini
2015-09-15 20:11 ` Sebastian Schütte
2015-10-28 22:56 ` [Bug 103321] " bugzilla-daemon
2015-10-28 22:56 ` bugzilla-daemon
2015-10-28 23:13 ` bugzilla-daemon
2015-10-28 23:51 ` bugzilla-daemon
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