Date: Sun, 25 Oct 2015 18:06:01 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 203874] MSI/MSI-X interrupts don't work in VMware virtual machines Message-ID: <bug-203874-8-GJ7tegkGPW@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-203874-8@https.bugs.freebsd.org/bugzilla/> References: <bug-203874-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=203874 --- Comment #4 from Marius Strobl <marius@FreeBSD.org> --- (In reply to bhavesh from comment #3) The problem with broken versions of ESXi is that allocation of MSI-X vectors fails when tried for the first time but succeeds on subsequent attempts. As Jack Vogel from Intel pointed out, this behavior inherently reminds of a design bug in Linux/KVM: https://lists.freebsd.org/pipermail/freebsd-stable/2012-October/070220.html The full thread starts here: https://lists.freebsd.org/pipermail/freebsd-stable/2012-October/070196.html I think at that time igb(4) additionally had an orthogonal and meanwhile fixed bug, causing it to fail to properly fall back to MSI or even INTx, leading to an overall non-working default setup when run under ESXi back then. Apart from that, there was a private and independent report to jhb@freebsd.org and me in June 2013, indicating that using INTx with ESXi 5.1 causes interrupt storms on the FreeBSD side. In addition to the VMware documentation of that time listing only three devices known-working with MSI-X in pass-through mode, this lead to the conclusion that MSIs are the only thing that reliably works with ESXi. Consequently, the current behavior of blacklisting the VMware PCI bridges for MSI-X (but contrary to your claim, not for MSI) was implemented and verified to yield a configuration which works out-of-the-box in the known problematic setups involving ESXi. As for the MSI-X allocation bug, it likely isn't/wasn't present in the bridge code of ESXi itself but rather in its LAPIC emulation. Still, bumping the PCI revision IDs to indicate ESXi versions where that problem has been fixed would be way preferable to having to query the hypervisor version by other means in the machine-independant PCI code of FreeBSD for limiting the blacklist entries for VMware. -- You are receiving this mail because: You are the assignee for the bug.
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