Message ID | 20240906173709.17861-1-bethany.jamison@canonical.com |
---|---|
Headers | show |
Series | disable XSAVES workaround | expand |
Acked-by: Thibault Ferrante <thibault.ferrante@canonical.com> On 06-09-2024 19:37, Bethany Jamison wrote: > BugLink: https://bugs.launchpad.net/bugs/2077321 Why does the bug is written as Confirmed for oracular even if the fix commit is already there as it was merged in 6.10 > > SRU Justification: > > [Impact] > > This patch fixes bug LP#2077321. An older commit (b056346) completely > disables XSAVES instruction on all AMD ZEN1/2 hardware to avoid a bug > within that instruction (utilizes XSAVEC instruction instead). This > method of working around this issue is a bit too broad and causes an > issue with migrating QEMU VMs from older kernels that use XSAVES to > newer kernels with XSAVES disabled. This patch implements a commit > (29ba89f) to improve the workaround. It disables XSAVES only on > machines that lack a revised piece of microcode that addresses the > XSAVES bug. > > [Fix] > > Above Commits: > b056346 (x86/CPU/AMD: Disable XSAVES on AMD family 0x17) - https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy/commit/?id=b0563468eeac88ebc70559d52a0b66efc37e4e9d > 29ba89f (x86/CPU/AMD: Improve the erratum 1386 workaround) - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=29ba89f1895285f06c333546882e0c5ae9a6df23 > > Commit 29ba89f was cleanly cherry-pick to Noble. I had to adjust the > context for Jammy because J was missing the definition for 'fix_erratum_1386', > but this should not affect the fix changes. > > [Test] > > Compile tested > > [Where problems could occur] > > This fix affects those who use x86 processors, an issue with this fix > would be visible to the user via issues migrating QEMU VMs from older > to newer kernels, or via XSAVEC being used instead of XSAVES in qualified > machines. > > v2: adjusted to better match the stable patch format > > v3: submited v2 too soon, needed to add impact/fix/test/problems sections > > Borislav Petkov (AMD) (1): > x86/CPU/AMD: Improve the erratum 1386 workaround > > arch/x86/include/asm/cpu_device_id.h | 8 ++++++++ > arch/x86/kernel/cpu/amd.c | 12 ++++++++++++ > 2 files changed, 20 insertions(+) >