kvm doesn't work on 36 physical bits systems

[Thadeu Lima de Souza Cascardo]

[Impact]
A guest will hang while booting under 4.18.0-10.11 because of "kvm: x86: Set highest physical address bits in non-present/reserved SPTEs", which came in via 4.18.y.

[Test Case]
A guest was booted after applying the patch.

[Regression Potential]
It might break KVM on systems with different physical memory limits, which is just what upstream might have been testing the most.

============

A fix is already upstream, and already present in 4.18.14.

This would be upstream commit
daa07cbc9ae3da2d61b7ce900c0b9107d134f2c1 ("KVM: x86: fix L1TF's MMIO GFN calculation").

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-cosmic' to 'verification-done-cosmic'. If the problem still exists, change the tag 'verification-needed-cosmic' to 'verification-failed-cosmic'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Thadeu Lima de Souza Cascardo (cascardo)]

Tested with 4.18.0-11, and it is working fine now.

Thanks.
Cascardo.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.18.0-11.12

---------------
linux (4.18.0-11.12) cosmic; urgency=medium

  * linux: 4.18.0-11.12 -proposed tracker (LP: #1799445)

  * arm64: snapdragon: WARNING: CPU: 0 PID: 1 arch/arm64/kernel/setup.c:271
    reserve_memblock_reserved_regions (LP: #1797139)
    - SAUCE: arm64: Fix /proc/iomem for reserved but not memory regions

  * arm64: snapdragon: WARNING: CPU: 0 PID: 1 at drivers/irqchip/irq-gic.c:1016
    gic_irq_domain_translate (LP: #1797143)
    - SAUCE: arm64: dts: msm8916: camms: fix gic_irq_domain_translate warnings

  * The front MIC can't work on the Lenovo M715 (LP: #1797292)
    - ALSA: hda/realtek - Fix the problem of the front MIC on the Lenovo M715

  * Provide mode where all vCPUs on a core must be the same VM (LP: #1792957)
    - KVM: PPC: Book3S HV: Provide mode where all vCPUs on a core must be the same
      VM

  * fscache: bad refcounting in fscache_op_complete leads to OOPS (LP: #1797314)
    - SAUCE: fscache: Fix race in decrementing refcount of op->npages

  * hns3: autoneg settings get lost on down/up (LP: #1797654)
    - net: hns3: Fix for information of phydev lost problem when down/up

  * not able to unwind the stack from within __kernel_clock_gettime in the Linux
    vDSO (LP: #1797963)
    - powerpc/vdso: Correct call frame information

  * Signal 7 error when running GPFS tracing in cluster (LP: #1792195)
    - powerpc/mm/books3s: Add new pte bit to mark pte temporarily invalid.
    - powerpc/mm/radix: Only need the Nest MMU workaround for R -> RW transition

  * Support Edge Gateway's WIFI LED (LP: #1798330)
    - SAUCE: mwifiex: Switch WiFi LED state according to the device status

  * Support Edge Gateway's Bluetooth LED (LP: #1798332)
    - SAUCE: Bluetooth: Support for LED on Edge Gateways

  * kvm doesn't work on 36 physical bits systems (LP: #1798427)
    - KVM: x86: fix L1TF's MMIO GFN calculation

  * CVE-2018-15471
    - xen-netback: fix input validation in xenvif_set_hash_mapping()

  * regression in 'ip --family bridge neigh' since linux v4.12 (LP: #1796748)
    - rtnetlink: fix rtnl_fdb_dump() for ndmsg header

 -- Stefan Bader <email address hidden> Tue, 23 Oct 2018 18:59:15 +0200