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Commit c13d1683 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

arm64: KVM: Implement fpsimd save/restore 



Implement the fpsimd save restore, keeping the lazy part in
assembler (as returning to C would be overkill).

Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent be901e9b

arch/arm64/kvm/hyp/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,3 +9,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o 
obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += entry.o

obj-$(CONFIG_KVM_ARM_HOST) += switch.o

obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o

arch/arm64/kvm/hyp/entry.S

+31 −1
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 


#define CPU_GP_REG_OFFSET(x)	(CPU_GP_REGS + x)

#define CPU_XREG_OFFSET(x)	CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)

#define CPU_SYSREG_OFFSET(x)	(CPU_SYSREGS + 8*x)



	.text

	.pushsection	.hyp.text, "ax"
@@ -127,4 +128,33 @@ ENTRY(__guest_exit) 
	ret

ENDPROC(__guest_exit)



	/* Insert fault handling here */
 
ENTRY(__fpsimd_guest_restore)

	stp	x4, lr, [sp, #-16]!



	mrs	x2, cptr_el2

	bic	x2, x2, #CPTR_EL2_TFP

	msr	cptr_el2, x2

	isb



	mrs	x3, tpidr_el2



	ldr	x0, [x3, #VCPU_HOST_CONTEXT]

	kern_hyp_va x0

	add	x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)

	bl	__fpsimd_save_state



	add	x2, x3, #VCPU_CONTEXT

	add	x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)

	bl	__fpsimd_restore_state



	mrs	x1, hcr_el2

	tbnz	x1, #HCR_RW_SHIFT, 1f

	ldr	x4, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)]

	msr	fpexc32_el2, x4

1:

	ldp	x4, lr, [sp], #16

	ldp	x2, x3, [sp], #16

	ldp	x0, x1, [sp], #16



	eret

ENDPROC(__fpsimd_guest_restore)

arch/arm64/kvm/hyp/fpsimd.S

0 → 100644
+33 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2015 - ARM Ltd

 * Author: Marc Zyngier <marc.zyngier@arm.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */



#include <linux/linkage.h>



#include <asm/fpsimdmacros.h>



	.text

	.pushsection	.hyp.text, "ax"



ENTRY(__fpsimd_save_state)

	fpsimd_save	x0, 1

	ret

ENDPROC(__fpsimd_save_state)



ENTRY(__fpsimd_restore_state)

	fpsimd_restore	x0, 1

	ret

ENDPROC(__fpsimd_restore_state)

arch/arm64/kvm/hyp/hyp.h

+7 −0
Original line number Diff line number Diff line
@@ -76,6 +76,13 @@ void __debug_restore_state(struct kvm_vcpu *vcpu, 
void __debug_cond_save_host_state(struct kvm_vcpu *vcpu);

void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);



void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);

void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);

static inline bool __fpsimd_enabled(void)

{

	return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);

}



u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);



#endif /* __ARM64_KVM_HYP_H__ */

arch/arm64/kvm/hyp/switch.c

+8 −0
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu) 
{

	struct kvm_cpu_context *host_ctxt;

	struct kvm_cpu_context *guest_ctxt;

	bool fp_enabled;

	u64 exit_code;



	vcpu = kern_hyp_va(vcpu);
@@ -118,6 +119,8 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu) 
	exit_code = __guest_enter(vcpu, host_ctxt);

	/* And we're baaack! */



	fp_enabled = __fpsimd_enabled();



	__sysreg_save_state(guest_ctxt);

	__sysreg32_save_state(vcpu);

	__timer_save_state(vcpu);
@@ -128,6 +131,11 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu) 


	__sysreg_restore_state(host_ctxt);



	if (fp_enabled) {

		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);

		__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);

	}



	__debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);

	__debug_cond_restore_host_state(vcpu);