Re: [PATCH v3 10/22] arm64: KVM: Implement guest entry

2015-12-14 Thread Christoffer Dall 
On Mon, Dec 07, 2015 at 10:53:26AM +, Marc Zyngier wrote:
> Contrary to the previous patch, the guest entry is fairly different
> from its assembly counterpart, mostly because it is only concerned
> with saving/restoring the GP registers, and nothing else.
> 
> Signed-off-by: Marc Zyngier 
> ---
>  arch/arm64/kvm/hyp/Makefile |   1 +
>  arch/arm64/kvm/hyp/entry.S  | 131 
> 
>  arch/arm64/kvm/hyp/hyp.h|   2 +
>  3 files changed, 134 insertions(+)
>  create mode 100644 arch/arm64/kvm/hyp/entry.S
> 
> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
> index ec14cac..1e1ff06 100644
> --- a/arch/arm64/kvm/hyp/Makefile
> +++ b/arch/arm64/kvm/hyp/Makefile
> @@ -7,3 +7,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o
>  obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o
>  obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
>  obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o
> +obj-$(CONFIG_KVM_ARM_HOST) += entry.o
> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
> new file mode 100644
> index 000..47f3c69
> --- /dev/null
> +++ b/arch/arm64/kvm/hyp/entry.S
> @@ -0,0 +1,131 @@
> +/*
> + * Copyright (C) 2015 - ARM Ltd
> + * Author: Marc Zyngier 
> + *
> + * 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 .
> + */
> +
> +#include 
> +
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +#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)
> +
> + .text
> + .pushsection.hyp.text, "ax"
> +
> +.macro save_callee_saved_regs ctxt
> + stp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
> + stp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
> + stp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
> + stp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
> + stp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
> + stp x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
> +.endm
> +
> +.macro restore_callee_saved_regs ctxt
> + ldp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
> + ldp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
> + ldp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
> + ldp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
> + ldp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
> + ldp x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
> +.endm
> +
> +/*
> + * u64 __guest_enter(struct kvm_vcpu *vcpu,
> + *struct kvm_cpu_context *host_ctxt);
> + */
> +ENTRY(__guest_enter)
> + // x0: vcpu
> + // x1: host/guest context
> + // x2-x18: clobbered by macros
> +
> + // Store the host regs
> + save_callee_saved_regs x1
> +
> + // Preserve vcpu & host_ctxt for use at exit time
> + stp x0, x1, [sp, #-16]!
> +
> + add x1, x0, #VCPU_CONTEXT
> +
> + // Prepare x0-x1 for later restore by pushing them onto the stack
> + ldp x2, x3, [x1, #CPU_XREG_OFFSET(0)]
> + stp x2, x3, [sp, #-16]!
> +
> + // x2-x18
> + ldp x2, x3,   [x1, #CPU_XREG_OFFSET(2)]
> + ldp x4, x5,   [x1, #CPU_XREG_OFFSET(4)]
> + ldp x6, x7,   [x1, #CPU_XREG_OFFSET(6)]
> + ldp x8, x9,   [x1, #CPU_XREG_OFFSET(8)]
> + ldp x10, x11, [x1, #CPU_XREG_OFFSET(10)]
> + ldp x12, x13, [x1, #CPU_XREG_OFFSET(12)]
> + ldp x14, x15, [x1, #CPU_XREG_OFFSET(14)]
> + ldp x16, x17, [x1, #CPU_XREG_OFFSET(16)]
> + ldr x18,  [x1, #CPU_XREG_OFFSET(18)]
> +
> + // x19-x29, lr
> + restore_callee_saved_regs x1
> +
> + // Last bits of the 64bit state
> + ldp x0, x1, [sp], #16
> +
> + // Do not touch any register after this!
> + eret
> +ENDPROC(__guest_enter)
> +
> +ENTRY(__guest_exit)
> + // x0: vcpu
> + // x1: return code
> + // x2-x3: free
> + // x4-x29,lr: vcpu regs
> + // vcpu x0-x3 on the stack
> +
> + add x2, x0, #VCPU_CONTEXT
> +
> + // Compute base to save registers

misleading comment again?  Or misplaced at least?

> + stp x4, x5,   [x2, #CPU_XREG_OFFSET(4)]
> + stp x6, x7,   [x2, #CPU_XREG_OFFSET(6)]
> + stp x8, x9,   [x2, #CPU_XREG_OFFSET(8)]
> + stp x10, x11, [x2, #CPU_XREG_OFFSET(10)]
> + stp x12, x13, [x2, #CPU_XREG_OFFSET(12)]
> + stp x14, x15, [x2, #CPU_XREG_OFFSET(14)]
> + stp x16, x17, [x2, #CPU_XREG_OFFSET(16)]
> + str

[PATCH v3 10/22] arm64: KVM: Implement guest entry

2015-12-07 Thread Marc Zyngier 
Contrary to the previous patch, the guest entry is fairly different
from its assembly counterpart, mostly because it is only concerned
with saving/restoring the GP registers, and nothing else.

Signed-off-by: Marc Zyngier 
---
 arch/arm64/kvm/hyp/Makefile |   1 +
 arch/arm64/kvm/hyp/entry.S  | 131 
 arch/arm64/kvm/hyp/hyp.h|   2 +
 3 files changed, 134 insertions(+)
 create mode 100644 arch/arm64/kvm/hyp/entry.S

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index ec14cac..1e1ff06 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o
+obj-$(CONFIG_KVM_ARM_HOST) += entry.o
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
new file mode 100644
index 000..47f3c69
--- /dev/null
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2015 - ARM Ltd
+ * Author: Marc Zyngier 
+ *
+ * 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 .
+ */
+
+#include 
+
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+#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)
+
+   .text
+   .pushsection.hyp.text, "ax"
+
+.macro save_callee_saved_regs ctxt
+   stp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
+   stp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
+   stp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
+   stp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
+   stp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
+   stp x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
+.endm
+
+.macro restore_callee_saved_regs ctxt
+   ldp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]
+   ldp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]
+   ldp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]
+   ldp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]
+   ldp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]
+   ldp x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]
+.endm
+
+/*
+ * u64 __guest_enter(struct kvm_vcpu *vcpu,
+ *  struct kvm_cpu_context *host_ctxt);
+ */
+ENTRY(__guest_enter)
+   // x0: vcpu
+   // x1: host/guest context
+   // x2-x18: clobbered by macros
+
+   // Store the host regs
+   save_callee_saved_regs x1
+
+   // Preserve vcpu & host_ctxt for use at exit time
+   stp x0, x1, [sp, #-16]!
+
+   add x1, x0, #VCPU_CONTEXT
+
+   // Prepare x0-x1 for later restore by pushing them onto the stack
+   ldp x2, x3, [x1, #CPU_XREG_OFFSET(0)]
+   stp x2, x3, [sp, #-16]!
+
+   // x2-x18
+   ldp x2, x3,   [x1, #CPU_XREG_OFFSET(2)]
+   ldp x4, x5,   [x1, #CPU_XREG_OFFSET(4)]
+   ldp x6, x7,   [x1, #CPU_XREG_OFFSET(6)]
+   ldp x8, x9,   [x1, #CPU_XREG_OFFSET(8)]
+   ldp x10, x11, [x1, #CPU_XREG_OFFSET(10)]
+   ldp x12, x13, [x1, #CPU_XREG_OFFSET(12)]
+   ldp x14, x15, [x1, #CPU_XREG_OFFSET(14)]
+   ldp x16, x17, [x1, #CPU_XREG_OFFSET(16)]
+   ldr x18,  [x1, #CPU_XREG_OFFSET(18)]
+
+   // x19-x29, lr
+   restore_callee_saved_regs x1
+
+   // Last bits of the 64bit state
+   ldp x0, x1, [sp], #16
+
+   // Do not touch any register after this!
+   eret
+ENDPROC(__guest_enter)
+
+ENTRY(__guest_exit)
+   // x0: vcpu
+   // x1: return code
+   // x2-x3: free
+   // x4-x29,lr: vcpu regs
+   // vcpu x0-x3 on the stack
+
+   add x2, x0, #VCPU_CONTEXT
+
+   // Compute base to save registers
+   stp x4, x5,   [x2, #CPU_XREG_OFFSET(4)]
+   stp x6, x7,   [x2, #CPU_XREG_OFFSET(6)]
+   stp x8, x9,   [x2, #CPU_XREG_OFFSET(8)]
+   stp x10, x11, [x2, #CPU_XREG_OFFSET(10)]
+   stp x12, x13, [x2, #CPU_XREG_OFFSET(12)]
+   stp x14, x15, [x2, #CPU_XREG_OFFSET(14)]
+   stp x16, x17, [x2, #CPU_XREG_OFFSET(16)]
+   str x18,  [x2, #CPU_XREG_OFFSET(18)]
+
+   ldp x6, x7, [sp], #16   // x2, x3
+   ldp x4, x5, [sp], #16   // x0, x1
+
+   stp x4, x5, [x2, #CPU_XREG_OFFSET(0)]
+   stp x6, x7, [x2, #CPU_XREG_OFFSET(2)]
+
+   save_callee_saved_regs