MIPS; KVM: Convert exception entry to uasm

Convert the whole of locore.S (assembly to enter guest and handle
exception entry) to be generated dynamically with uasm. This is done
with minimal changes to the resulting code.

The main changes are:
- Some constants are generated by uasm using LUI+ADDIU instead of
  LUI+ORI.
- Loading of lo and hi are swapped around in vcpu_run but not when
  resuming the guest after an exit. Both bits of logic are now generated
  by the same code.
- Register MOVEs in uasm use different ADDU operand ordering to GNU as,
  putting zero register into rs instead of rt.
- The JALR.HB to call the C exit handler is switched to JALR, since the
  hazard barrier would appear to be unnecessary.

This will allow further optimisation in the future to dynamically handle
the capabilities of the CPU.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <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>

1 files changed, 12 insertions, 25 deletions

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 5f1163653b50..e3ae1229f147 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -247,8 +247,8 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 {
-	int err, size, offset;
-	void *gebase;
+	int err, size;
+	void *gebase, *p;
 	int i;
 
 	struct kvm_vcpu *vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
@@ -286,41 +286,28 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 	/* Save new ebase */
 	vcpu->arch.guest_ebase = gebase;
 
-	/* Copy L1 Guest Exception handler to correct offset */
+	/* Build guest exception vectors dynamically in unmapped memory */
 
 	/* TLB Refill, EXL = 0 */
-	memcpy(gebase, mips32_exception,
-	       mips32_exceptionEnd - mips32_exception);
+	kvm_mips_build_exception(gebase);
 
 	/* General Exception Entry point */
-	memcpy(gebase + 0x180, mips32_exception,
-	       mips32_exceptionEnd - mips32_exception);
+	kvm_mips_build_exception(gebase + 0x180);
 
 	/* For vectored interrupts poke the exception code @ all offsets 0-7 */
 	for (i = 0; i < 8; i++) {
 		kvm_debug("L1 Vectored handler @ %p\n",
 			  gebase + 0x200 + (i * VECTORSPACING));
-		memcpy(gebase + 0x200 + (i * VECTORSPACING), mips32_exception,
-		       mips32_exceptionEnd - mips32_exception);
+		kvm_mips_build_exception(gebase + 0x200 + i * VECTORSPACING);
 	}
 
-	/* General handler, relocate to unmapped space for sanity's sake */
-	offset = 0x2000;
-	kvm_debug("Installing KVM Exception handlers @ %p, %#x bytes\n",
-		  gebase + offset,
-		  mips32_GuestExceptionEnd - mips32_GuestException);
+	/* General exit handler */
+	p = gebase + 0x2000;
+	p = kvm_mips_build_exit(p);
 
-	memcpy(gebase + offset, mips32_GuestException,
-	       mips32_GuestExceptionEnd - mips32_GuestException);
-
-#ifdef MODULE
-	offset += mips32_GuestExceptionEnd - mips32_GuestException;
-	memcpy(gebase + offset, (char *)__kvm_mips_vcpu_run,
-	       __kvm_mips_vcpu_run_end - (char *)__kvm_mips_vcpu_run);
-	vcpu->arch.vcpu_run = gebase + offset;
-#else
-	vcpu->arch.vcpu_run = __kvm_mips_vcpu_run;
-#endif
+	/* Guest entry routine */
+	vcpu->arch.vcpu_run = p;
+	p = kvm_mips_build_vcpu_run(p);
 
 	/* Invalidate the icache for these ranges */
 	local_flush_icache_range((unsigned long)gebase,