diff options
| author | James Hogan <james.hogan@imgtec.com> | 2016-06-09 14:19:14 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-06-14 11:02:44 +0200 |
| commit | 878edf014e29de38c49153aba20273fbc9ae31af (patch) | |
| tree | 0ea5871f8a035389da5aa423e72a0a58f2033473 | |
| parent | 26ee17ff71d3def831bfa4f6851ed1ba789e24f6 (diff) | |
| download | linux-878edf014e29de38c49153aba20273fbc9ae31af.tar.gz linux-878edf014e29de38c49153aba20273fbc9ae31af.tar.bz2 linux-878edf014e29de38c49153aba20273fbc9ae31af.zip | |
MIPS: KVM: Restore host EBase from ebase variable
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>
| -rw-r--r-- | arch/mips/include/asm/kvm_host.h | 2 | ||||
| -rw-r--r-- | arch/mips/kernel/asm-offsets.c | 1 | ||||
| -rw-r--r-- | arch/mips/kernel/traps.c | 1 | ||||
| -rw-r--r-- | arch/mips/kvm/locore.S | 2 | ||||
| -rw-r--r-- | arch/mips/kvm/mips.c | 3 |
5 files changed, 3 insertions, 6 deletions
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index f68293b4a598..24a8e557db88 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -334,7 +334,7 @@ struct kvm_mips_tlb { #define KVM_MIPS_GUEST_TLB_SIZE 64 struct kvm_vcpu_arch { - void *host_ebase, *guest_ebase; + void *guest_ebase; int (*vcpu_run)(struct kvm_run *run, struct kvm_vcpu *vcpu); unsigned long host_stack; unsigned long host_gp; diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c index 420808899c70..a1263d188a5a 100644 --- a/arch/mips/kernel/asm-offsets.c +++ b/arch/mips/kernel/asm-offsets.c @@ -355,7 +355,6 @@ void output_kvm_defines(void) OFFSET(VCPU_RUN, kvm_vcpu, run); OFFSET(VCPU_HOST_ARCH, kvm_vcpu, arch); - OFFSET(VCPU_HOST_EBASE, kvm_vcpu_arch, host_ebase); OFFSET(VCPU_GUEST_EBASE, kvm_vcpu_arch, guest_ebase); OFFSET(VCPU_HOST_STACK, kvm_vcpu_arch, host_stack); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 4a1712b5abdf..66e5820bfdae 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -1859,6 +1859,7 @@ void __noreturn nmi_exception_handler(struct pt_regs *regs) #define VECTORSPACING 0x100 /* for EI/VI mode */ unsigned long ebase; +EXPORT_SYMBOL_GPL(ebase); unsigned long exception_handlers[32]; unsigned long vi_handlers[64]; diff --git a/arch/mips/kvm/locore.S b/arch/mips/kvm/locore.S index 43c8ef847efa..f87bec546366 100644 --- a/arch/mips/kvm/locore.S +++ b/arch/mips/kvm/locore.S @@ -319,7 +319,7 @@ NESTED (MIPSX(GuestException), CALLFRAME_SIZ, ra) mtc0 k0, CP0_STATUS ehb - LONG_L k0, VCPU_HOST_EBASE(k1) + LONG_L k0, ebase mtc0 k0,CP0_EBASE /* diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index c1ab6110ca1d..6e753761b5d6 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -273,9 +273,6 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) else size = 0x4000; - /* Save Linux EBASE */ - vcpu->arch.host_ebase = (void *)read_c0_ebase(); - gebase = kzalloc(ALIGN(size, PAGE_SIZE), GFP_KERNEL); if (!gebase) { |