[PATCH 12/21] arm64: KVM: Implement fpsimd save/restore
Marc Zyngier
marc.zyngier at arm.com
Mon Nov 16 05:11:50 PST 2015
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 at arm.com>
---
arch/arm64/kvm/hyp/Makefile | 1 +
arch/arm64/kvm/hyp/entry.S | 32 +++++++++++++++++++++++++++++++-
arch/arm64/kvm/hyp/fpsimd.S | 33 +++++++++++++++++++++++++++++++++
arch/arm64/kvm/hyp/hyp.h | 3 +++
arch/arm64/kvm/hyp/switch.c | 8 ++++++++
5 files changed, 76 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/kvm/hyp/fpsimd.S
diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index 9c11b0f..56238d0 100644
--- 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 2c4449a..7552922 100644
--- 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"
@@ -152,4 +153,33 @@ ENTRY(__guest_exit)
ret
ENDPROC(__guest_exit)
- /* Insert fault handling here */
+ENTRY(__fpsimd_guest_restore)
+ push x4, lr
+
+ 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:
+ pop x4, lr
+ pop x2, x3
+ pop x0, x1
+
+ 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
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 at 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 bf13238..240fb79 100644
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -70,6 +70,9 @@ void __debug_clear_restore_state(struct kvm_vcpu *vcpu,
struct kvm_guest_debug_arch *dbg,
struct kvm_cpu_context *ctxt);
+void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
+void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
+
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 a3af81a..06d3e20 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -88,6 +88,7 @@ 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);
@@ -117,6 +118,8 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
exit_code = __guest_enter(vcpu, host_ctxt);
/* And we're baaack! */
+ fp_enabled = !!(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
+
__sysreg_save_state(guest_ctxt);
__sysreg32_save_state(vcpu);
__timer_save_state(vcpu);
@@ -127,6 +130,11 @@ 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, &vcpu->arch.vcpu_debug_state, guest_ctxt);
__debug_clear_restore_state(vcpu, &vcpu->arch.host_debug_state, host_ctxt);
--
2.1.4
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