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 <m.smarduch@xxxxxxxxxxx>
---
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
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