This patch implements the VFP context switch code called from vcpu_put in Host KVM. In addition it implements the logic to skip setting a VFP trap if one is not needed. Also resets the flag if Host KVM switched registers to trap new guest vfp accesses.
Signed-off-by: Mario Smarduch <[email protected]> --- arch/arm/kvm/interrupts.S | 49 ++++++++++++++++++++++++++++----------------- 1 file changed, 31 insertions(+), 18 deletions(-) diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S index 79caf79..0912edd 100644 --- a/arch/arm/kvm/interrupts.S +++ b/arch/arm/kvm/interrupts.S @@ -96,6 +96,21 @@ ENTRY(__kvm_flush_vm_context) bx lr ENDPROC(__kvm_flush_vm_context) +ENTRY(__kvm_restore_host_vfp_state) + push {r3-r7} + + mov r1, #0 + str r1, [r0, #VCPU_VFP_SAVED] + + add r7, r0, #VCPU_VFP_GUEST + store_vfp_state r7 + add r7, r0, #VCPU_VFP_HOST + ldr r7, [r7] + restore_vfp_state r7 + + pop {r3-r7} + bx lr +ENDPROC(__kvm_restore_host_vfp_state) /******************************************************************** * Hypervisor world-switch code @@ -131,7 +146,13 @@ ENTRY(__kvm_vcpu_run) @ Trap coprocessor CRx accesses set_hstr vmentry + + ldr r1, [vcpu, #VCPU_VFP_SAVED] + cmp r1, #1 + beq skip_guest_vfp_trap set_hcptr vmentry, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) +skip_guest_vfp_trap: + set_hdcr vmentry @ Write configured ID register into MIDR alias @@ -173,18 +194,6 @@ __kvm_vcpu_return: set_hcptr vmexit, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) #ifdef CONFIG_VFPv3 - @ Save floating point registers we if let guest use them. - tst r2, #(HCPTR_TCP(10) | HCPTR_TCP(11)) - bne after_vfp_restore - - @ Switch VFP/NEON hardware state to the host's - add r7, vcpu, #VCPU_VFP_GUEST - store_vfp_state r7 - add r7, vcpu, #VCPU_VFP_HOST - ldr r7, [r7] - restore_vfp_state r7 - -after_vfp_restore: @ Restore FPEXC_EN which we clobbered on entry pop {r2} VFPFMXR FPEXC, r2 @@ -363,10 +372,6 @@ hyp_hvc: @ Check syndrome register mrc p15, 4, r1, c5, c2, 0 @ HSR lsr r0, r1, #HSR_EC_SHIFT -#ifdef CONFIG_VFPv3 - cmp r0, #HSR_EC_CP_0_13 - beq switch_to_guest_vfp -#endif cmp r0, #HSR_EC_HVC bne guest_trap @ Not HVC instr. @@ -380,7 +385,10 @@ hyp_hvc: cmp r2, #0 bne guest_trap @ Guest called HVC -host_switch_to_hyp: + /* + * Getting here means host called HVC, we shift parameters and branch + * to Hyp function. + */ pop {r0, r1, r2} /* Check for __hyp_get_vectors */ @@ -411,6 +419,10 @@ guest_trap: @ Check if we need the fault information lsr r1, r1, #HSR_EC_SHIFT +#ifdef CONFIG_VFPv3 + cmp r1, #HSR_EC_CP_0_13 + beq switch_to_guest_vfp +#endif cmp r1, #HSR_EC_IABT mrceq p15, 4, r2, c6, c0, 2 @ HIFAR beq 2f @@ -479,11 +491,12 @@ guest_trap: */ #ifdef CONFIG_VFPv3 switch_to_guest_vfp: - load_vcpu @ Load VCPU pointer to r0 push {r3-r7} @ NEON/VFP used. Turn on VFP access. set_hcptr vmexit, (HCPTR_TCP(10) | HCPTR_TCP(11)) + mov r1, #1 + str r1, [vcpu, #VCPU_VFP_SAVED] @ Switch VFP/NEON hardware state to the guest's add r7, r0, #VCPU_VFP_HOST -- 1.7.9.5 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
