(Re-)enable IOMMU for Intel GPU

[marmarek]

Drop iommu=no-igfx option.
See #2836 (comment)

[rustybird]

Weird: Booting the 20170718 R4.0 prerelease on a T420 (latest proprietary BIOS) with iommu=no-igfx results in a Xen panic - I see "BIOS did not enable IGD for VT properly, crash Xen for security purpose" after adding console=vga. But iommu=force appears to works fine!

[rustybird]

Weird: Booting the 20170718 R4.0 prerelease on a T420 (latest proprietary BIOS) with iommu=no-igfx results in a Xen panic - I see "BIOS did not enable IGD for VT properly, crash Xen for security purpose" after adding console=vga. But iommu=force appears to works fine!

[marmarek]

On Wed, Jul 26, 2017 at 01:28:26PM -0700, Rusty Bird wrote: Weird: Booting the 20170718 R4.0 prerelease on a T420 (latest proprietary BIOS) with `iommu=no-igfx` results in a Xen panic - I see "BIOS did not enable IGD for VT properly, crash Xen for security purpose" after adding `console=vga`. But `iommu=force` appears to works fine!

That's indeed interesting behaviour. Glad it works with IOMMU for you!

…

-- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing?

[marmarek]

On Wed, Jul 26, 2017 at 01:28:26PM -0700, Rusty Bird wrote: Weird: Booting the 20170718 R4.0 prerelease on a T420 (latest proprietary BIOS) with `iommu=no-igfx` results in a Xen panic - I see "BIOS did not enable IGD for VT properly, crash Xen for security purpose" after adding `console=vga`. But `iommu=force` appears to works fine!

That's indeed interesting behaviour. Glad it works with IOMMU for you!

…

-- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing?

[rustybird]

Seems to be this:

• force_iommu can be enabled not only by iommu=force, but also automatically by x2apic_bsp_setup() in some cases (such as the T420, apparently)

• iommu_enable_translation() generates a warning when force_iommu is off, or a panic when force_iommu is on, if is_igd_vt_enabled_quirk() returns 0. Even if the reason it returns 0 is just iommu=no-igfx.

I'll submit a patch to xen-devel.

[rustybird]

Seems to be this:

• force_iommu can be enabled not only by iommu=force, but also automatically by x2apic_bsp_setup() in some cases (such as the T420, apparently)

• iommu_enable_translation() generates a warning when force_iommu is off, or a panic when force_iommu is on, if is_igd_vt_enabled_quirk() returns 0. Even if the reason it returns 0 is just iommu=no-igfx.

I'll submit a patch to xen-devel.

[mex20]

This issue also occurs on Microsoft UEFI devices. I had a heck of a time figuring out why 4.0 RC1 would get stuck in a boot loop after displaying the loading Xen 4.8.1 text on the Surface boot screen. Changing “iommu=no-igfx” to “iommu=on” fixed the boot loop.

[mex20]

This issue also occurs on Microsoft UEFI devices. I had a heck of a time figuring out why 4.0 RC1 would get stuck in a boot loop after displaying the loading Xen 4.8.1 text on the Surface boot screen. Changing “iommu=no-igfx” to “iommu=on” fixed the boot loop.

[josephcsible]

With Qubes OS 4.0RC4 in UEFI mode on Intel HD Graphics 4000, I needed to add iommu=no-igfx to not just get a black screen. This wasn't a problem until I upgraded from RC3.

[josephcsible]

With Qubes OS 4.0RC4 in UEFI mode on Intel HD Graphics 4000, I needed to add iommu=no-igfx to not just get a black screen. This wasn't a problem until I upgraded from RC3.

[RooneyMcNibNug]

I'm possibly having the same issue since 4.0 on a T420 with regular graphics. Installation went fine (tested with multiple installation mediums, including two different USBs and a CD), but bootup shows "squashed" text and then gets stuck at a blank screen where I should be seeing the LVM password field.

The "squashed" bootup I'm seeing is almost exactly the same as the one shown in this post: https://www.reddit.com/r/Qubes/comments/7wheqk/does_anyone_else_get_this_weird_screen_glitch/

[RooneyMcNibNug]

I'm possibly having the same issue since 4.0 on a T420 with regular graphics. Installation went fine (tested with multiple installation mediums, including two different USBs and a CD), but bootup shows "squashed" text and then gets stuck at a blank screen where I should be seeing the LVM password field.

The "squashed" bootup I'm seeing is almost exactly the same as the one shown in this post: https://www.reddit.com/r/Qubes/comments/7wheqk/does_anyone_else_get_this_weird_screen_glitch/

[tasket]

I had to remove iommu=no-igfx from Xen options after configuring anti-evil-maid. Otherwise the AEM bootup resulted in unusable garbage screen and i915 "GPU hang" errors. This is on an Ivy Bridge laptop with integrated graphics.

[tasket]

I had to remove iommu=no-igfx from Xen options after configuring anti-evil-maid. Otherwise the AEM bootup resulted in unusable garbage screen and i915 "GPU hang" errors. This is on an Ivy Bridge laptop with integrated graphics.