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>

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index 9c11b0fe164695dbae5cd797dadfe72410987a38..56238d08d36f162e3dcfa3cc7c9928fd42d9590a 100644 (file)
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -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

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index ff196951e63b9bdf556f2433b3f6eabe31389aef..90cbf0fee88ae3eae4ee34f6b04a852fd53d8eac 100644 (file)
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -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)

diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
new file mode 100644 (file)
index 0000000..da3f22c
--- /dev/null
+++ b/arch/arm64/kvm/hyp/fpsimd.S
@@ -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)

diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index 73419a769112fbc01c822e063e57fd77f12c6341..70d4f696c8620fec977b10d19926798380979649 100644 (file)
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -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__ */

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 79f59c98b14821937a3a2068904baea1d1bfcb2f..608155f5b8562d1a817aee34f34174014904de0e 100644 (file)
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -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);
 

diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index eb05afb77ee83eab39d0271de6482872bc98b5e8..36035417ec52f2a54127a5070f4bdfb39ba37044 100644 (file)
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -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)