[ipxe-devel] [PATCH 0/2] mask lack of KVM's FXSAVE/FXRSTOR emulation in the QEMU build

Laszlo Ersek lersek at redhat.com
Wed Oct 26 22:13:49 UTC 2016

iPXE commit 71560d185475 added FXSAVE and FXRSTOR instructions. On KVM
hosts without "unrestricted_guest" support, these expose a gap in KVM's
big real mode emulation, leading to guest crashes.

Radim has just posted the KVM patches. I think it might make sense to
suppress the regression of user experience within iPXE, until the KVM
feature reaches end-users. (Especially because the workaround for the
Tivoli VMM bug, which needed the FXSAVE and FXRSTOR instructions, is not
useful on KVM.)

Cc: Bandan Das <bsd at redhat.com>
Cc: Gerd Hoffmann <kraxel at redhat.com>
Cc: Greg <rollenwiese at yahoo.com>
Cc: Michael Brown <mcb30 at ipxe.org>
Cc: Michael Prokop <launchpad at michael-prokop.at>
Cc: Paolo Bonzini <pbonzini at redhat.com>
Cc: Peter Pickford <arch at netremedies.ca>
Cc: Radim Krčmář <rkrcmar at redhat.com>


Laszlo Ersek (2):
  [librm] Conditionalize the workaround for the Tivoli VMM's SSE
  [build] Disable TIVOLI_VMM_WORKAROUND in the qemu configuration

 src/config/general.h             |  3 +++
 src/config/qemu/general.h        |  5 +++++
 src/arch/x86/transitions/librm.S | 15 ++++++++++++++-
 3 files changed, 22 insertions(+), 1 deletion(-)


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