[PATCH 16/29] arm64: KVM: HYP mode world switch implementation

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The HYP mode world switch in all its glory.

Implements save/restore of host/guest registers, EL2 trapping,
IPA resolution, and additional services (tlb invalidation).

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
 arch/arm64/kernel/asm-offsets.c |  33 ++
 arch/arm64/kvm/hyp.S            | 756 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 789 insertions(+)
 create mode 100644 arch/arm64/kvm/hyp.S

diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index a2a4d81..a7f706a 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -21,6 +21,7 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
+#include <linux/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
 #include <asm/cputable.h>
@@ -104,5 +105,37 @@ int main(void)
   BLANK();
   DEFINE(TZ_MINWEST,		offsetof(struct timezone, tz_minuteswest));
   DEFINE(TZ_DSTTIME,		offsetof(struct timezone, tz_dsttime));
+  BLANK();
+#ifdef CONFIG_KVM_ARM_HOST
+  DEFINE(VCPU_REGS,		offsetof(struct kvm_vcpu, arch.regs));
+  DEFINE(VCPU_USER_PT_REGS,	offsetof(struct kvm_regs, regs));
+  DEFINE(VCPU_VFP_GUEST,	offsetof(struct kvm_vcpu, arch.vfp_guest));
+  DEFINE(VCPU_VFP_HOST,		offsetof(struct kvm_vcpu, arch.vfp_host));
+  DEFINE(VCPU_HCR_EL2,		offsetof(struct kvm_vcpu, arch.hcr_el2));
+  DEFINE(VCPU_IRQ_LINES,	offsetof(struct kvm_vcpu, arch.irq_lines));
+  DEFINE(VCPU_SP_EL1,		offsetof(struct kvm_vcpu, arch.regs.sp_el1));
+  DEFINE(VCPU_ELR_EL1,		offsetof(struct kvm_vcpu, arch.regs.elr_el1));
+  DEFINE(VCPU_SPSR,		offsetof(struct kvm_vcpu, arch.regs.spsr));
+  DEFINE(VCPU_SYSREGS,		offsetof(struct kvm_vcpu, arch.sys_regs));
+  DEFINE(VCPU_ESR_EL2,		offsetof(struct kvm_vcpu, arch.fault.esr_el2));
+  DEFINE(VCPU_FAR_EL2,		offsetof(struct kvm_vcpu, arch.fault.far_el2));
+  DEFINE(VCPU_HPFAR_EL2,	offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
+  DEFINE(VCPU_TIMER_CNTV_CTL,	offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl));
+  DEFINE(VCPU_TIMER_CNTV_CVAL,	offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_cval));
+  DEFINE(KVM_TIMER_CNTVOFF,	offsetof(struct kvm, arch.timer.cntvoff));
+  DEFINE(KVM_TIMER_ENABLED,	offsetof(struct kvm, arch.timer.enabled));
+  DEFINE(VCPU_KVM,		offsetof(struct kvm_vcpu, kvm));
+  DEFINE(VCPU_VGIC_CPU,		offsetof(struct kvm_vcpu, arch.vgic_cpu));
+  DEFINE(VGIC_CPU_HCR,		offsetof(struct vgic_cpu, vgic_hcr));
+  DEFINE(VGIC_CPU_VMCR,		offsetof(struct vgic_cpu, vgic_vmcr));
+  DEFINE(VGIC_CPU_MISR,		offsetof(struct vgic_cpu, vgic_misr));
+  DEFINE(VGIC_CPU_EISR,		offsetof(struct vgic_cpu, vgic_eisr));
+  DEFINE(VGIC_CPU_ELRSR,	offsetof(struct vgic_cpu, vgic_elrsr));
+  DEFINE(VGIC_CPU_APR,		offsetof(struct vgic_cpu, vgic_apr));
+  DEFINE(VGIC_CPU_LR,		offsetof(struct vgic_cpu, vgic_lr));
+  DEFINE(VGIC_CPU_NR_LR,	offsetof(struct vgic_cpu, nr_lr));
+  DEFINE(KVM_VTTBR,		offsetof(struct kvm, arch.vttbr));
+  DEFINE(KVM_VGIC_VCTRL,	offsetof(struct kvm, arch.vgic.vctrl_base));
+#endif
   return 0;
 }
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
new file mode 100644
index 0000000..cd7506d
--- /dev/null
+++ b/arch/arm64/kvm/hyp.S
@@ -0,0 +1,756 @@
+/*
+ * Copyright (C) 2012 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@xxxxxxx>
+ *
+ * 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 <linux/irqchip/arm-gic.h>
+
+#include <asm/assembler.h>
+#include <asm/memory.h>
+#include <asm/asm-offsets.h>
+#include <asm/fpsimdmacros.h>
+#include <asm/kvm.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_mmu.h>
+
+#define REG_OFFSET(x)		(VCPU_REGS + VCPU_USER_PT_REGS + 8*x)
+#define SPSR_OFFSET(x)		(VCPU_SPSR + 8*x)
+#define SYSREG_OFFSET(x)	(VCPU_SYSREGS + 8*x)
+
+	.text
+	.pushsection	.hyp.text, "ax"
+	.align	PAGE_SHIFT
+
+__kvm_hyp_code_start:
+	.globl __kvm_hyp_code_start
+
+.macro save_host_regs
+	push	x19, x20
+	push	x21, x22
+	push	x23, x24
+	push	x25, x26
+	push	x27, x28
+	push	x29, lr
+
+	mrs	x19, sp_el0
+	mrs	x20, sp_el1
+	mrs	x21, elr_el1
+	mrs	x22, spsr_el1
+	mrs	x23, elr_el2
+	mrs	x24, spsr_el2
+
+	push	x19, x20
+	push	x21, x22
+	push	x23, x24
+.endm
+
+.macro restore_host_regs
+	pop	x23, x24
+	pop	x21, x22
+	pop	x19, x20
+
+	msr	sp_el0, x19
+	msr	sp_el1,	x20
+	msr	elr_el1, x21
+	msr	spsr_el1, x22
+	msr	elr_el2, x23
+	msr	spsr_el2, x24
+
+	pop	x29, lr
+	pop	x27, x28
+	pop	x25, x26
+	pop	x23, x24
+	pop	x21, x22
+	pop	x19, x20
+.endm
+
+.macro save_host_fpsimd
+	// X0: vcpu address
+	// x2, x3: tmp regs
+	ldr	x2, [x0, #VCPU_VFP_HOST]
+	kern_hyp_va x2
+	fpsimd_save x2, 3
+.endm
+
+.macro restore_host_fpsimd
+	// X0: vcpu address
+	// x2, x3: tmp regs
+	ldr	x2, [x0, #VCPU_VFP_HOST]
+	kern_hyp_va x2
+	fpsimd_restore x2, 3
+.endm
+
+.macro save_guest_regs
+	// x0 is the vcpu address.
+	// x1 is the return code, do not corrupt!
+	// Guest's x0-x3 are on the stack
+
+	// Compute base to save registers
+	add	x2, x0, #REG_OFFSET(4)
+	mrs	x3, sp_el0
+	stp	x4, x5, [x2], #16
+	stp	x6, x7, [x2], #16
+	stp	x8, x9, [x2], #16
+	stp	x10, x11, [x2], #16
+	stp	x12, x13, [x2], #16
+	stp	x14, x15, [x2], #16
+	stp	x16, x17, [x2], #16
+	stp	x18, x19, [x2], #16
+	stp	x20, x21, [x2], #16
+	stp	x22, x23, [x2], #16
+	stp	x24, x25, [x2], #16
+	stp	x26, x27, [x2], #16
+	stp	x28, x29, [x2], #16
+	stp	lr, x3, [x2], #16	// LR, SP_EL0
+
+	mrs	x4, elr_el2		// PC
+	mrs	x5, spsr_el2		// CPSR
+	stp	x4, x5, [x2], #16
+
+	pop	x6, x7			// x2, x3
+	pop	x4, x5			// x0, x1
+
+	add	x2, x0, #REG_OFFSET(0)
+	stp	x4, x5, [x2], #16
+	stp	x6, x7, [x2], #16
+
+	// EL1 state
+	mrs	x4, sp_el1
+	mrs	x5, elr_el1
+	mrs	x6, spsr_el1
+	str	x4, [x0, #VCPU_SP_EL1]
+	str	x5, [x0, #VCPU_ELR_EL1]
+	str	x6, [x0, #SPSR_OFFSET(KVM_SPSR_EL1)]
+.endm
+
+.macro restore_guest_regs
+	// x0 is the vcpu address.
+
+	// EL1 state
+	ldr	x4, [x0, #VCPU_SP_EL1]
+	ldr	x5, [x0, #VCPU_ELR_EL1]
+	ldr	x6, [x0, #SPSR_OFFSET(KVM_SPSR_EL1)]
+	msr	sp_el1, x4
+	msr	elr_el1, x5
+	msr	spsr_el1, x6
+
+	// Prepare x0-x3 for later restore
+	add	x1, x0, #REG_OFFSET(0)
+	ldp	x4, x5, [x1], #16
+	ldp	x6, x7, [x1], #16
+	push	x4, x5		// Push x0-x3 on the stack
+	push	x6, x7
+
+	// x4-x29, lr, sp_el0
+	ldp	x4, x5, [x1], #16
+	ldp	x6, x7, [x1], #16
+	ldp	x8, x9, [x1], #16
+	ldp	x10, x11, [x1], #16
+	ldp	x12, x13, [x1], #16
+	ldp	x14, x15, [x1], #16
+	ldp	x16, x17, [x1], #16
+	ldp	x18, x19, [x1], #16
+	ldp	x20, x21, [x1], #16
+	ldp	x22, x23, [x1], #16
+	ldp	x24, x25, [x1], #16
+	ldp	x26, x27, [x1], #16
+	ldp	x28, x29, [x1], #16
+	ldp	lr, x3, [x1], #16
+	msr	sp_el0, x3
+
+	// PC, cpsr
+	ldp	x2, x3, [x1]
+	msr	elr_el2, x2
+	msr	spsr_el2, x3
+
+	// Last bits of the 64bit state
+	pop	x2, x3
+	pop	x0, x1
+
+	// Do not touch any register after this!
+.endm
+
+.macro save_guest_fpsimd
+	// X0: vcpu address
+	// x2, x3: tmp regs
+	add	x2, x0, #VCPU_VFP_GUEST
+	fpsimd_save x2, 3
+.endm
+
+.macro restore_guest_fpsimd
+	// X0: vcpu address
+	// x2, x3: tmp regs
+	add	x2, x0, #VCPU_VFP_GUEST
+	fpsimd_restore x2, 3
+.endm
+
+/*
+ * Macros to perform system register save/restore.
+ *
+ * Ordering here is absolutely critical, and must be kept consistent
+ * in dump_sysregs, load_sysregs, {save,restore}_guest_sysregs,
+ * {save,restore}_guest_32bit_state, and in kvm_asm.h.
+ *
+ * In other words, don't touch any of these unless you know what
+ * you are doing.
+ */
+.macro dump_sysregs
+	mrs	x4,	mpidr_el1
+	mrs	x5,	csselr_el1
+	mrs	x6,	sctlr_el1
+	mrs	x7,	actlr_el1
+	mrs	x8,	cpacr_el1
+	mrs	x9,	ttbr0_el1
+	mrs	x10,	ttbr1_el1
+	mrs	x11,	tcr_el1
+	mrs	x12,	esr_el1
+	mrs	x13, 	afsr0_el1
+	mrs	x14,	afsr1_el1
+	mrs	x15,	far_el1
+	mrs	x16,	mair_el1
+	mrs	x17,	vbar_el1
+	mrs	x18,	contextidr_el1
+	mrs	x19,	tpidr_el0
+	mrs	x20,	tpidrro_el0
+	mrs	x21,	tpidr_el1
+	mrs	x22, 	amair_el1
+	mrs	x23, 	cntkctl_el1
+.endm
+
+.macro load_sysregs
+	msr	vmpidr_el2,	x4
+	msr	csselr_el1,	x5
+	msr	sctlr_el1,	x6
+	msr	actlr_el1,	x7
+	msr	cpacr_el1,	x8
+	msr	ttbr0_el1,	x9
+	msr	ttbr1_el1,	x10
+	msr	tcr_el1,	x11
+	msr	esr_el1,	x12
+	msr	afsr0_el1,	x13
+	msr	afsr1_el1,	x14
+	msr	far_el1,	x15
+	msr	mair_el1,	x16
+	msr	vbar_el1,	x17
+	msr	contextidr_el1,	x18
+	msr	tpidr_el0,	x19
+	msr	tpidrro_el0,	x20
+	msr	tpidr_el1,	x21
+	msr	amair_el1,	x22
+	msr	cntkctl_el1,	x23
+.endm
+
+.macro save_host_sysregs
+	dump_sysregs
+	push	x4, x5
+	push	x6, x7
+	push	x8, x9
+	push	x10, x11
+	push	x12, x13
+	push	x14, x15
+	push	x16, x17
+	push	x18, x19
+	push	x20, x21
+	push	x22, x23
+.endm
+
+.macro save_guest_sysregs
+	dump_sysregs
+	add	x2, x0, #SYSREG_OFFSET(CSSELR_EL1) // MIPDR_EL2 not written back
+	str	x5, [x2], #8
+	stp	x6, x7, [x2], #16
+	stp	x8, x9, [x2], #16
+	stp	x10, x11, [x2], #16
+	stp	x12, x13, [x2], #16
+	stp	x14, x15, [x2], #16
+	stp	x16, x17, [x2], #16
+	stp	x18, x19, [x2], #16
+	stp	x20, x21, [x2], #16
+	stp	x22, x23, [x2], #16
+.endm
+
+.macro restore_host_sysregs
+	pop	x22, x23
+	pop	x20, x21
+	pop	x18, x19
+	pop	x16, x17
+	pop	x14, x15
+	pop	x12, x13
+	pop	x10, x11
+	pop	x8, x9
+	pop	x6, x7
+	pop	x4, x5
+	load_sysregs
+.endm
+
+.macro restore_guest_sysregs
+	add	x2, x0, #SYSREG_OFFSET(MPIDR_EL1)
+	ldp	x4, x5, [x2], #16
+	ldp	x6, x7, [x2], #16
+	ldp	x8, x9, [x2], #16
+	ldp	x10, x11, [x2], #16
+	ldp	x12, x13, [x2], #16
+	ldp	x14, x15, [x2], #16
+	ldp	x16, x17, [x2], #16
+	ldp	x18, x19, [x2], #16
+	ldp	x20, x21, [x2], #16
+	ldp	x22, x23, [x2], #16
+	load_sysregs
+.endm
+
+.macro activate_traps
+	ldr	x2, [x0, #VCPU_IRQ_LINES]
+	ldr	x1, [x0, #VCPU_HCR_EL2]
+	orr	x2, x2, x1
+	msr	hcr_el2, x2
+
+	ldr	x2, =(CPTR_EL2_TTA)
+	msr	cptr_el2, x2
+
+	ldr	x2, =(1 << 15)	// Trap CP15 Cr=15
+	msr	hstr_el2, x2
+
+	mrs	x2, mdcr_el2
+	and	x2, x2, #MDCR_EL2_HPMN_MASK
+	orr	x2, x2, #(MDCR_EL2_TPM | MDCR_EL2_TPMCR)
+	msr	mdcr_el2, x2
+.endm
+
+.macro deactivate_traps
+	mov	x2, #HCR_RW
+	msr	hcr_el2, x2
+	msr	cptr_el2, xzr
+	msr	hstr_el2, xzr
+
+	mrs	x2, mdcr_el2
+	and	x2, x2, #MDCR_EL2_HPMN_MASK
+	msr	mdcr_el2, x2
+.endm
+
+.macro activate_vm
+	ldr	x1, [x0, #VCPU_KVM]
+	kern_hyp_va	x1
+	ldr	x2, [x1, #KVM_VTTBR]
+	msr	vttbr_el2, x2
+.endm
+
+.macro deactivate_vm
+	msr	vttbr_el2, xzr
+.endm
+
+/*
+ * Save the VGIC CPU state into memory
+ * x0: Register pointing to VCPU struct
+ * Do not corrupt x1!!!
+ */
+.macro save_vgic_state
+	/* Get VGIC VCTRL base into x2 */
+	ldr	x2, [x0, #VCPU_KVM]
+	kern_hyp_va	x2
+	ldr	x2, [x2, #KVM_VGIC_VCTRL]
+	kern_hyp_va	x2
+	cbz	x2, 2f		// disabled
+
+	/* Compute the address of struct vgic_cpu */
+	add	x3, x0, #VCPU_VGIC_CPU
+
+	/* Save all interesting registers */
+	ldr	w4, [x2, #GICH_HCR]
+	ldr	w5, [x2, #GICH_VMCR]
+	ldr	w6, [x2, #GICH_MISR]
+	ldr	w7, [x2, #GICH_EISR0]
+	ldr	w8, [x2, #GICH_EISR1]
+	ldr	w9, [x2, #GICH_ELRSR0]
+	ldr	w10, [x2, #GICH_ELRSR1]
+	ldr	w11, [x2, #GICH_APR]
+
+	str	w4, [x3, #VGIC_CPU_HCR]
+	str	w5, [x3, #VGIC_CPU_VMCR]
+	str	w6, [x3, #VGIC_CPU_MISR]
+	str	w7, [x3, #VGIC_CPU_EISR]
+	str	w8, [x3, #(VGIC_CPU_EISR + 4)]
+	str	w9, [x3, #VGIC_CPU_ELRSR]
+	str	w10, [x3, #(VGIC_CPU_ELRSR + 4)]
+	str	w11, [x3, #VGIC_CPU_APR]
+
+	/* Clear GICH_HCR */
+	str	wzr, [x2, #GICH_HCR]
+
+	/* Save list registers */
+	add	x2, x2, #GICH_LR0
+	ldr	w4, [x3, #VGIC_CPU_NR_LR]
+	add	x3, x3, #VGIC_CPU_LR
+1:	ldr	w5, [x2], #4
+	str	w5, [x3], #4
+	sub	w4, w4, #1
+	cbnz	w4, 1b
+2:
+.endm
+
+/*
+ * Restore the VGIC CPU state from memory
+ * x0: Register pointing to VCPU struct
+ */
+.macro restore_vgic_state
+	/* Get VGIC VCTRL base into x2 */
+	ldr	x2, [x0, #VCPU_KVM]
+	kern_hyp_va	x2
+	ldr	x2, [x2, #KVM_VGIC_VCTRL]
+	kern_hyp_va	x2
+	cbz	x2, 2f		// disabled
+
+	/* Compute the address of struct vgic_cpu */
+	add	x3, x0, #VCPU_VGIC_CPU
+
+	/* We only restore a minimal set of registers */
+	ldr	w4, [x3, #VGIC_CPU_HCR]
+	ldr	w5, [x3, #VGIC_CPU_VMCR]
+	ldr	w6, [x3, #VGIC_CPU_APR]
+
+	str	w4, [x2, #GICH_HCR]
+	str	w5, [x2, #GICH_VMCR]
+	str	w6, [x2, #GICH_APR]
+
+	/* Restore list registers */
+	add	x2, x2, #GICH_LR0
+	ldr	w4, [x3, #VGIC_CPU_NR_LR]
+	add	x3, x3, #VGIC_CPU_LR
+1:	ldr	w5, [x3], #4
+	str	w5, [x2], #4
+	sub	w4, w4, #1
+	cbnz	w4, 1b
+2:
+.endm
+
+.macro save_timer_state
+	ldr	x2, [x0, #VCPU_KVM]
+	kern_hyp_va x2
+	ldr	w3, [x2, #KVM_TIMER_ENABLED]
+	cbz	w3, 1f
+
+	mrs	x3, cntv_ctl_el0
+	and	x3, x3, #3
+	str	w3, [x0, #VCPU_TIMER_CNTV_CTL]
+	bic	x3, x3, #1		// Clear Enable
+	msr	cntv_ctl_el0, x3
+
+	isb
+
+	mrs	x3, cntv_cval_el0
+	str	x3, [x0, #VCPU_TIMER_CNTV_CVAL]
+
+1:
+	// Allow physical timer/counter access for the host
+	mrs	x2, cnthctl_el2
+	orr	x2, x2, #3
+	msr	cnthctl_el2, x2
+
+	// Clear cntvoff for the host
+	msr	cntvoff_el2, xzr
+.endm
+
+.macro restore_timer_state vcpup
+	// Disallow physical timer access for the guest
+	// Physical counter access is allowed
+	mrs	x2, cnthctl_el2
+	orr	x2, x2, #1
+	bic	x2, x2, #2
+	msr	cnthctl_el2, x2
+
+	ldr	x2, [x0, #VCPU_KVM]
+	kern_hyp_va x2
+	ldr	w3, [x2, #KVM_TIMER_ENABLED]
+	cbz	w3, 1f
+
+	ldr	x3, [x2, #KVM_TIMER_CNTVOFF]
+	msr	cntvoff_el2, x3
+	ldr	x2, [x0, #VCPU_TIMER_CNTV_CVAL]
+	msr	cntv_cval_el0, x2
+	isb
+
+	ldr	w2, [x0, #VCPU_TIMER_CNTV_CTL]
+	and	x2, x2, #3
+	msr	cntv_ctl_el0, x2
+1:
+.endm
+
+/*
+ * u64 __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+ *
+ * This is the world switch. The first half of the function
+ * deals with entering the guest, and anything from __kvm_vcpu_return
+ * to the end of the function deals with reentering the host.
+ * On the enter path, only x0 (vcpu pointer) must be preserved until
+ * the last moment. On the exit path, x0 (vcpu pointer) and x1 (exception
+ * code) must both be preserved until the epilogue.
+ */
+ENTRY(__kvm_vcpu_run)
+	kern_hyp_va	x0
+	msr	tpidr_el2, x0	// Save the vcpu register
+
+	save_host_regs
+	save_host_fpsimd
+	save_host_sysregs
+
+	activate_traps
+	activate_vm
+
+	restore_vgic_state
+	restore_timer_state
+	restore_guest_sysregs
+	restore_guest_fpsimd
+	restore_guest_regs
+
+	// That's it, no more messing around.
+	clrex
+	eret
+
+__kvm_vcpu_return:
+	// Assume x0 is the vcpu pointer, x1 the return code
+	// Guest's x0-x3 are on the stack
+	save_guest_regs
+	save_guest_fpsimd
+	save_guest_sysregs
+	save_timer_state
+	save_vgic_state
+
+	deactivate_traps
+	deactivate_vm
+
+	restore_host_sysregs
+	restore_host_fpsimd
+	restore_host_regs
+	mov	x0, x1
+	clrex
+	ret
+END(__kvm_vcpu_run)
+
+// void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa);
+ENTRY(__kvm_tlb_flush_vmid_ipa)
+	kern_hyp_va	x0
+	ldr	x2, [x0, #KVM_VTTBR]
+	msr	vttbr_el2, x2
+	isb
+
+	/*
+	 * We could do so much better if we had the VA as well.
+	 * Instead, we invalidate Stage-2 for this IPA, and the
+	 * whole of Stage-1. Weep...
+	 */
+	tlbi	ipas2e1is, x1
+	dsb	sy
+	tlbi	vmalle1is
+	dsb	sy
+	isb
+
+	msr	vttbr_el2, xzr
+	isb
+	ret
+ENDPROC(__kvm_tlb_flush_vmid_ipa)
+
+ENTRY(__kvm_flush_vm_context)
+	tlbi	alle1is
+	ic	ialluis
+	dsb	sy
+	isb
+	ret
+ENDPROC(__kvm_flush_vm_context)
+
+__kvm_hyp_panic:
+	adr	x0, __hyp_panic_str
+	adr	x1, 1f
+	ldp	x2, x3, [x1]
+	sub	x0, x0, x2
+	add	x0, x0, x3
+	mrs	x1, spsr_el2
+	mrs	x2, elr_el2
+	mrs	x3, esr_el2
+	mrs	x4, far_el2
+	mrs	x5, hpfar_el2
+	mrs	x6, tpidr_el2
+
+	mov	lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
+		      PSR_MODE_EL1h)
+	msr	spsr_el2, lr
+	ldr	lr, =panic
+	msr	elr_el2, lr
+	eret
+
+	.align	3
+1:	.quad	HYP_PAGE_OFFSET
+	.quad	PAGE_OFFSET
+ENDPROC(__kvm_hyp_panic)
+
+__hyp_panic_str:
+	.ascii	"HYP panic:\nPS:%08x PC:%p ESR:%p\nFAR:%p HPFAR:%p VCPU:%p\n\0"
+
+	.align	2
+
+ENTRY(kvm_call_hyp)
+	hvc	#0
+	ret
+ENDPROC(kvm_call_hyp)
+
+.macro invalid_vector	label, target
+	.align	2
+\label:
+	b \target
+ENDPROC(\label)
+.endm
+
+	/* None of these should ever happen */
+	invalid_vector	el2t_sync_invalid, __kvm_hyp_panic
+	invalid_vector	el2t_irq_invalid, __kvm_hyp_panic
+	invalid_vector	el2t_fiq_invalid, __kvm_hyp_panic
+	invalid_vector	el2t_error_invalid, __kvm_hyp_panic
+	invalid_vector	el2h_sync_invalid, __kvm_hyp_panic
+	invalid_vector	el2h_irq_invalid, __kvm_hyp_panic
+	invalid_vector	el2h_fiq_invalid, __kvm_hyp_panic
+	invalid_vector	el2h_error_invalid, __kvm_hyp_panic
+	invalid_vector	el1_sync_invalid, __kvm_hyp_panic
+	invalid_vector	el1_irq_invalid, __kvm_hyp_panic
+	invalid_vector	el1_fiq_invalid, __kvm_hyp_panic
+	invalid_vector	el1_error_invalid, __kvm_hyp_panic
+
+el1_sync:					// Guest trapped into EL2
+	push	x0, x1
+	push	x2, x3
+
+	mrs	x1, esr_el2
+	lsr	x2, x1, #ESR_EL2_EC_SHIFT
+
+	cmp	x2, #ESR_EL2_EC_HVC64
+	b.ne	el1_trap
+
+	mrs	x3, vttbr_el2			// If vttbr is valid, the 64bit guest
+	cbnz	x3, el1_trap			// called HVC
+
+	/* Here, we're pretty sure the host called HVC. */
+	pop	x2, x3
+	pop	x0, x1
+
+	push	lr, xzr
+
+	/*
+	 * Compute the function address in EL2, and shuffle the parameters.
+	 */
+	kern_hyp_va	x0
+	mov	lr, x0
+	mov	x0, x1
+	mov	x1, x2
+	mov	x2, x3
+	blr	lr
+
+	pop	lr, xzr
+	eret
+
+el1_trap:
+	/*
+	 * x1: ESR
+	 * x2: ESR_EC
+	 */
+	cmp	x2, #ESR_EL2_EC_DABT
+	mov	x0, #ESR_EL2_EC_IABT
+	ccmp	x2, x0, #4, ne
+	b.ne	1f		// Not an abort we care about
+
+	/* This is an abort. Check for permission fault */
+	and	x2, x1, #ESR_EL2_FSC_TYPE
+	cmp	x2, #FSC_PERM
+	b.ne	1f		// Not a permission fault
+
+	/*
+	 * Check for Stage-1 page table walk, which is guaranteed
+	 * to give a valid HPFAR_EL2.
+	 */
+	tbnz	x1, #7, 1f	// S1PTW is set
+
+	/*
+	 * Permission fault, HPFAR_EL2 is invalid.
+	 * Resolve the IPA the hard way using the guest VA.
+	 * We always perform an EL1 lookup, as we already
+	 * went through Stage-1.
+	 */
+	mrs	x3, far_el2
+	at	s1e1r, x3
+	isb
+
+	/* Read result */
+	mrs	x3, par_el1
+	tbnz	x3, #1, 3f		// Bail out if we failed the translation
+	ubfx	x3, x3, #12, #36	// Extract IPA
+	lsl	x3, x3, #4		// and present it like HPFAR
+	b	2f
+
+1:	mrs	x3, hpfar_el2
+
+2:	mrs	x0, tpidr_el2
+	mrs	x2, far_el2
+	str	x1, [x0, #VCPU_ESR_EL2]
+	str	x2, [x0, #VCPU_FAR_EL2]
+	str	x3, [x0, #VCPU_HPFAR_EL2]
+
+	mov	x1, #ARM_EXCEPTION_TRAP
+	b	__kvm_vcpu_return
+
+	/*
+	 * Translation failed. Just return to the guest and
+	 * let it fault again. Another CPU is probably playing
+	 * behind our back.
+	 */
+3:	pop	x2, x3
+	pop	x0, x1
+
+	eret
+
+el1_irq:
+	push	x0, x1
+	push	x2, x3
+	mrs	x0, tpidr_el2
+	mov	x1, #ARM_EXCEPTION_IRQ
+	b	__kvm_vcpu_return
+
+	.ltorg
+
+	.align 11
+
+ENTRY(__kvm_hyp_vector)
+	ventry	el2t_sync_invalid		// Synchronous EL2t
+	ventry	el2t_irq_invalid		// IRQ EL2t
+	ventry	el2t_fiq_invalid		// FIQ EL2t
+	ventry	el2t_error_invalid		// Error EL2t
+
+	ventry	el2h_sync_invalid		// Synchronous EL2h
+	ventry	el2h_irq_invalid		// IRQ EL2h
+	ventry	el2h_fiq_invalid		// FIQ EL2h
+	ventry	el2h_error_invalid		// Error EL2h
+
+	ventry	el1_sync			// Synchronous 64-bit EL1
+	ventry	el1_irq				// IRQ 64-bit EL1
+	ventry	el1_fiq_invalid			// FIQ 64-bit EL1
+	ventry	el1_error_invalid		// Error 64-bit EL1
+
+	ventry	el1_sync			// Synchronous 32-bit EL1
+	ventry	el1_irq				// IRQ 32-bit EL1
+	ventry	el1_fiq_invalid			// FIQ 32-bit EL1
+	ventry	el1_error_invalid		// Error 32-bit EL1
+ENDPROC(__kvm_hyp_vector)
+
+__kvm_hyp_code_end:
+	.globl	__kvm_hyp_code_end
+
+	.popsection
-- 
1.7.12.4

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