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: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier 2015-10-26 08:34:09 +00:00
parent be901e9b15
commit c13d1683df
6 changed files with 81 additions and 2 deletions

View File

@ -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

View File

@ -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)

View File

@ -0,0 +1,33 @@
/*
* 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)

View File

@ -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__ */

View File

@ -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);

View File

@ -107,7 +107,7 @@ void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
sysreg[DACR32_EL2] = read_sysreg(dacr32_el2);
sysreg[IFSR32_EL2] = read_sysreg(ifsr32_el2);
if (!(read_sysreg(cptr_el2) & CPTR_EL2_TFP))
if (__fpsimd_enabled())
sysreg[FPEXC32_EL2] = read_sysreg(fpexc32_el2);
if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY)