Date: Wed, 13 May 2015 10:14:18 +0200 From: =?UTF-8?B?Um9nZXIgUGF1IE1vbm7DqQ==?= <roger.pau@citrix.com> To: Ruslan Makhmatkhanov <cvs-src@yandex.ru>, <freebsd-xen@freebsd.org> Subject: Re: iommu must be enabled for PVH hardware domain Message-ID: <555307DA.2060303@citrix.com> In-Reply-To: <55530582.2070008@yandex.ru> References: <55521A29.9080409@yandex.ru> <5552212D.8090308@citrix.com> <55530582.2070008@yandex.ru>
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Hello, El 13/05/15 a les 10.04, Ruslan Makhmatkhanov ha escrit: > Roger Pau Monné wrote on 05/12/15 18:50: >> Hello, >> >> El 12/05/15 a les 17.20, Ruslan Makhmatkhanov ha escrit: >>> Hello, >>> >>> we have machine with VT-d and EPT-capable CPU: >>> Intel(R) Xeon(R) CPU E5504 [1] >>> >>> The system is FreeBSD 11.0-CURRENT r282694 installed from >>> ftp.freebsd.org iso. >>> >>> But dom0 fails to boot at this hardware with "iommu must be enabled for >>> PVH hardware domain" [2]. VT-d support is indeed not detected at kernel >>> level. Here is dmesg with VT-d enabled in BIOS [3] and dmesg with VT-d >>> disabled in BIOS [4]. It's look like there is no difference on both >>> outputs. Here is the proofpic of that the system is VT-d capable and the >>> support is enabled in BIOS [5]. Here is acpidump -t output [6] >> >> My bet right now is be that Xen detects that your IOMMU contains erratas >> and disables it. Can you add "iommu=debug,force" to your xen_cmdline and >> try again? >> >> Also, can you paste the contents of your /boot/loader.conf? >> >> Roger. > > You are right: > > [VT-D] Disabling IOMMU due to Intel 5500/5520/X58 Chipset errata #47, #53 > > and after that: > > ---------------------------------------------- > Panic on CPU 0: > Couldn't enable IOMMU and iommu=required/force > ---------------------------------------------- > > Reboot in five seconds. > > But what this means practically? Some chipset bugs preventing us to use > this feature. Can this circumvented somehow? Thanks. AFAIK iommu=force should force the usage of the IOMMU even if erratas are detected. You can also try with iommu=force,no-intremap. Roger.
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