linux_dsm_epyc7002/virt/kvm
Dave Martin 17eed27b02 arm64/sve: KVM: Prevent guests from using SVE
Until KVM has full SVE support, guests must not be allowed to
execute SVE instructions.

This patch enables the necessary traps, and also ensures that the
traps are disabled again on exit from the guest so that the host
can still use SVE if it wants to.

On guest exit, high bits of the SVE Zn registers may have been
clobbered as a side-effect the execution of FPSIMD instructions in
the guest.  The existing KVM host FPSIMD restore code is not
sufficient to restore these bits, so this patch explicitly marks
the CPU as not containing cached vector state for any task, thus
forcing a reload on the next return to userspace.  This is an
interim measure, in advance of adding full SVE awareness to KVM.

This marking of cached vector state in the CPU as invalid is done
using __this_cpu_write(fpsimd_last_state, NULL) in fpsimd.c.  Due
to the repeated use of this rather obscure operation, it makes
sense to factor it out as a separate helper with a clearer name.
This patch factors it out as fpsimd_flush_cpu_state(), and ports
all callers to use it.

As a side effect of this refactoring, a this_cpu_write() in
fpsimd_cpu_pm_notifier() is changed to __this_cpu_write().  This
should be fine, since cpu_pm_enter() is supposed to be called only
with interrupts disabled.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-11-03 15:24:19 +00:00
..
arm arm64/sve: KVM: Prevent guests from using SVE 2017-11-03 15:24:19 +00:00
async_pf.c kvm,async_pf: Use swq_has_sleeper() 2017-09-15 16:57:11 +02:00
async_pf.h KVM: fix checkpatch.pl errors in kvm/async_pf.h 2015-06-19 17:16:25 +02:00
coalesced_mmio.c KVM: move iodev.h from virt/kvm/ to include/kvm 2015-03-26 21:43:12 +00:00
coalesced_mmio.h KVM: make the declaration of functions within 80 characters 2015-09-14 18:43:19 +02:00
eventfd.c Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
irqchip.c KVM: use rcu access function for irq routing 2017-07-07 15:24:15 +02:00
Kconfig KVM: remove kvm_vcpu_compatible 2016-06-16 00:05:00 +02:00
kvm_main.c kvm: Serialize wq active checks in kvm_vcpu_wake_up() 2017-09-15 16:57:12 +02:00
vfio.c vfio: New external user group/file match 2017-06-28 13:50:05 -06:00
vfio.h kvm: vfio: fix unregister kvm_device_ops of vfio 2014-10-24 13:30:47 +02:00