MIPS: KVM: Restore host EBase from ebase variable

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The host kernel's exception vector base address is currently saved in
the VCPU structure at creation time, and restored on a guest exit.
However it doesn't change and can already be easily accessed from the
'ebase' variable (arch/mips/kernel/traps.c), so drop the host_ebase
member of kvm_vcpu_arch, export the 'ebase' variable to modules and load
from there instead.

This does result in a single extra instruction (lui) on the guest exit
path, but simplifies the code a bit and removes the redundant storage of
the host exception base address.

Credit for the idea goes to Cavium's VZ KVM implementation.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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This commit is contained in:

James Hogan 2016-06-09 14:19:14 +01:00 • committed by Paolo Bonzini

parent 26ee17ff71

commit 878edf014e

5 changed files with 3 additions and 6 deletions

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2

arch/mips/include/asm/kvm_host.h

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1

arch/mips/kernel/asm-offsets.c

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1

arch/mips/kernel/traps.c

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2

arch/mips/kvm/locore.S

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3

arch/mips/kvm/mips.c

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