Date: Sun, 30 Apr 2017 18:17:42 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-virtualization@FreeBSD.org Subject: [Bug 203994] bhyve kernel module may need to relax some checks when running nested under KVM Message-ID: <bug-203994-27103-QIjF13GzAg@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-203994-27103@https.bugs.freebsd.org/bugzilla/> References: <bug-203994-27103@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D203994 --- Comment #17 from Peter Grehan <grehan@FreeBSD.org> --- Just an update on this. I used Ubuntu since it was easy to get a range of L= inux kernel versions to test with. - Ubuntu 17.04 (kernel 4.10) works without any changes to bhyve - Ubuntu 15.10 doesn't advertize INVVPID capability. While it would be possible to modify bhyve to work in this mode, I'm loathe to do it since it= 's such a niche case - Ubuntu 16.04 seems to have the capabilities that most folk have reported. After modifying bhyve to ignore the unused INVVPID capabilities and to fall-back to the all-context INVEPT if single-context wasn't available, the next issue was that Linux/KVM wasn't setting the GLA on EPT faults. This is used by bhyve to verify the GLA that is also obtained through the instructi= on emulation path for guest MMIO operations. This verification path hasn't thr= own any errors for a few years now, so I relaxed this test when in this mode. (Of note, this bug was reported here https://lkml.org/lkml/2016/9/4/156, and the author has submitted a diff review to relax some of the INVVPID/INVEPT checks at https://reviews.freebsd.org/D10049) However, after doing all this, bhyve would still eventually panic with a ke= rnel trap-9 fault when issuing a vmread instruction, so there may still be some additional KVM bugs that are being hit on this kernel rev :( I'll do some more experimentation and then post the patch that I have. --=20 You are receiving this mail because: You are the assignee for the bug.=
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