308 lines
7.5 KiB
ArmAsm
308 lines
7.5 KiB
ArmAsm
|
/*
|
||
|
|
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
|
||
|
|
* Author: Christoffer Dall <c.dall@virtualopensystems.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, write to the Free Software
|
||
|
|
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/arm-smccc.h>
|
||
|
|
#include <linux/linkage.h>
|
||
|
|
#include <asm/kvm_arm.h>
|
||
|
|
#include <asm/kvm_asm.h>
|
||
|
|
|
||
|
|
.arch_extension virt
|
||
|
|
|
||
|
|
.text
|
||
|
|
.pushsection .hyp.text, "ax"
|
||
|
|
|
||
|
|
.macro load_vcpu reg
|
||
|
|
mrc p15, 4, \reg, c13, c0, 2 @ HTPIDR
|
||
|
|
.endm
|
||
|
|
|
||
|
|
/********************************************************************
|
||
|
|
* Hypervisor exception vector and handlers
|
||
|
|
*
|
||
|
|
*
|
||
|
|
* The KVM/ARM Hypervisor ABI is defined as follows:
|
||
|
|
*
|
||
|
|
* Entry to Hyp mode from the host kernel will happen _only_ when an HVC
|
||
|
|
* instruction is issued since all traps are disabled when running the host
|
||
|
|
* kernel as per the Hyp-mode initialization at boot time.
|
||
|
|
*
|
||
|
|
* HVC instructions cause a trap to the vector page + offset 0x14 (see hyp_hvc
|
||
|
|
* below) when the HVC instruction is called from SVC mode (i.e. a guest or the
|
||
|
|
* host kernel) and they cause a trap to the vector page + offset 0x8 when HVC
|
||
|
|
* instructions are called from within Hyp-mode.
|
||
|
|
*
|
||
|
|
* Hyp-ABI: Calling HYP-mode functions from host (in SVC mode):
|
||
|
|
* Switching to Hyp mode is done through a simple HVC #0 instruction. The
|
||
|
|
* exception vector code will check that the HVC comes from VMID==0.
|
||
|
|
* - r0 contains a pointer to a HYP function
|
||
|
|
* - r1, r2, and r3 contain arguments to the above function.
|
||
|
|
* - The HYP function will be called with its arguments in r0, r1 and r2.
|
||
|
|
* On HYP function return, we return directly to SVC.
|
||
|
|
*
|
||
|
|
* Note that the above is used to execute code in Hyp-mode from a host-kernel
|
||
|
|
* point of view, and is a different concept from performing a world-switch and
|
||
|
|
* executing guest code SVC mode (with a VMID != 0).
|
||
|
|
*/
|
||
|
|
|
||
|
|
.align 5
|
||
|
|
__kvm_hyp_vector:
|
||
|
|
.global __kvm_hyp_vector
|
||
|
|
|
||
|
|
@ Hyp-mode exception vector
|
||
|
|
W(b) hyp_reset
|
||
|
|
W(b) hyp_undef
|
||
|
|
W(b) hyp_svc
|
||
|
|
W(b) hyp_pabt
|
||
|
|
W(b) hyp_dabt
|
||
|
|
W(b) hyp_hvc
|
||
|
|
W(b) hyp_irq
|
||
|
|
W(b) hyp_fiq
|
||
|
|
|
||
|
|
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
|
||
|
|
.align 5
|
||
|
|
__kvm_hyp_vector_ic_inv:
|
||
|
|
.global __kvm_hyp_vector_ic_inv
|
||
|
|
|
||
|
|
/*
|
||
|
|
* We encode the exception entry in the bottom 3 bits of
|
||
|
|
* SP, and we have to guarantee to be 8 bytes aligned.
|
||
|
|
*/
|
||
|
|
W(add) sp, sp, #1 /* Reset 7 */
|
||
|
|
W(add) sp, sp, #1 /* Undef 6 */
|
||
|
|
W(add) sp, sp, #1 /* Syscall 5 */
|
||
|
|
W(add) sp, sp, #1 /* Prefetch abort 4 */
|
||
|
|
W(add) sp, sp, #1 /* Data abort 3 */
|
||
|
|
W(add) sp, sp, #1 /* HVC 2 */
|
||
|
|
W(add) sp, sp, #1 /* IRQ 1 */
|
||
|
|
W(nop) /* FIQ 0 */
|
||
|
|
|
||
|
|
mcr p15, 0, r0, c7, c5, 0 /* ICIALLU */
|
||
|
|
isb
|
||
|
|
|
||
|
|
b decode_vectors
|
||
|
|
|
||
|
|
.align 5
|
||
|
|
__kvm_hyp_vector_bp_inv:
|
||
|
|
.global __kvm_hyp_vector_bp_inv
|
||
|
|
|
||
|
|
/*
|
||
|
|
* We encode the exception entry in the bottom 3 bits of
|
||
|
|
* SP, and we have to guarantee to be 8 bytes aligned.
|
||
|
|
*/
|
||
|
|
W(add) sp, sp, #1 /* Reset 7 */
|
||
|
|
W(add) sp, sp, #1 /* Undef 6 */
|
||
|
|
W(add) sp, sp, #1 /* Syscall 5 */
|
||
|
|
W(add) sp, sp, #1 /* Prefetch abort 4 */
|
||
|
|
W(add) sp, sp, #1 /* Data abort 3 */
|
||
|
|
W(add) sp, sp, #1 /* HVC 2 */
|
||
|
|
W(add) sp, sp, #1 /* IRQ 1 */
|
||
|
|
W(nop) /* FIQ 0 */
|
||
|
|
|
||
|
|
mcr p15, 0, r0, c7, c5, 6 /* BPIALL */
|
||
|
|
isb
|
||
|
|
|
||
|
|
decode_vectors:
|
||
|
|
|
||
|
|
#ifdef CONFIG_THUMB2_KERNEL
|
||
|
|
/*
|
||
|
|
* Yet another silly hack: Use VPIDR as a temp register.
|
||
|
|
* Thumb2 is really a pain, as SP cannot be used with most
|
||
|
|
* of the bitwise instructions. The vect_br macro ensures
|
||
|
|
* things gets cleaned-up.
|
||
|
|
*/
|
||
|
|
mcr p15, 4, r0, c0, c0, 0 /* VPIDR */
|
||
|
|
mov r0, sp
|
||
|
|
and r0, r0, #7
|
||
|
|
sub sp, sp, r0
|
||
|
|
push {r1, r2}
|
||
|
|
mov r1, r0
|
||
|
|
mrc p15, 4, r0, c0, c0, 0 /* VPIDR */
|
||
|
|
mrc p15, 0, r2, c0, c0, 0 /* MIDR */
|
||
|
|
mcr p15, 4, r2, c0, c0, 0 /* VPIDR */
|
||
|
|
#endif
|
||
|
|
|
||
|
|
.macro vect_br val, targ
|
||
|
|
ARM( eor sp, sp, #\val )
|
||
|
|
ARM( tst sp, #7 )
|
||
|
|
ARM( eorne sp, sp, #\val )
|
||
|
|
|
||
|
|
THUMB( cmp r1, #\val )
|
||
|
|
THUMB( popeq {r1, r2} )
|
||
|
|
|
||
|
|
beq \targ
|
||
|
|
.endm
|
||
|
|
|
||
|
|
vect_br 0, hyp_fiq
|
||
|
|
vect_br 1, hyp_irq
|
||
|
|
vect_br 2, hyp_hvc
|
||
|
|
vect_br 3, hyp_dabt
|
||
|
|
vect_br 4, hyp_pabt
|
||
|
|
vect_br 5, hyp_svc
|
||
|
|
vect_br 6, hyp_undef
|
||
|
|
vect_br 7, hyp_reset
|
||
|
|
#endif
|
||
|
|
|
||
|
|
.macro invalid_vector label, cause
|
||
|
|
.align
|
||
|
|
\label: mov r0, #\cause
|
||
|
|
b __hyp_panic
|
||
|
|
.endm
|
||
|
|
|
||
|
|
invalid_vector hyp_reset ARM_EXCEPTION_RESET
|
||
|
|
invalid_vector hyp_undef ARM_EXCEPTION_UNDEFINED
|
||
|
|
invalid_vector hyp_svc ARM_EXCEPTION_SOFTWARE
|
||
|
|
invalid_vector hyp_pabt ARM_EXCEPTION_PREF_ABORT
|
||
|
|
invalid_vector hyp_fiq ARM_EXCEPTION_FIQ
|
||
|
|
|
||
|
|
ENTRY(__hyp_do_panic)
|
||
|
|
mrs lr, cpsr
|
||
|
|
bic lr, lr, #MODE_MASK
|
||
|
|
orr lr, lr, #SVC_MODE
|
||
|
|
THUMB( orr lr, lr, #PSR_T_BIT )
|
||
|
|
msr spsr_cxsf, lr
|
||
|
|
ldr lr, =panic
|
||
|
|
msr ELR_hyp, lr
|
||
|
|
ldr lr, =kvm_call_hyp
|
||
|
|
clrex
|
||
|
|
eret
|
||
|
|
ENDPROC(__hyp_do_panic)
|
||
|
|
|
||
|
|
hyp_hvc:
|
||
|
|
/*
|
||
|
|
* Getting here is either because of a trap from a guest,
|
||
|
|
* or from executing HVC from the host kernel, which means
|
||
|
|
* "do something in Hyp mode".
|
||
|
|
*/
|
||
|
|
push {r0, r1, r2}
|
||
|
|
|
||
|
|
@ Check syndrome register
|
||
|
|
mrc p15, 4, r1, c5, c2, 0 @ HSR
|
||
|
|
lsr r0, r1, #HSR_EC_SHIFT
|
||
|
|
cmp r0, #HSR_EC_HVC
|
||
|
|
bne guest_trap @ Not HVC instr.
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Let's check if the HVC came from VMID 0 and allow simple
|
||
|
|
* switch to Hyp mode
|
||
|
|
*/
|
||
|
|
mrrc p15, 6, r0, r2, c2
|
||
|
|
lsr r2, r2, #16
|
||
|
|
and r2, r2, #0xff
|
||
|
|
cmp r2, #0
|
||
|
|
bne guest_hvc_trap @ Guest called HVC
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Getting here means host called HVC, we shift parameters and branch
|
||
|
|
* to Hyp function.
|
||
|
|
*/
|
||
|
|
pop {r0, r1, r2}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Check if we have a kernel function, which is guaranteed to be
|
||
|
|
* bigger than the maximum hyp stub hypercall
|
||
|
|
*/
|
||
|
|
cmp r0, #HVC_STUB_HCALL_NR
|
||
|
|
bhs 1f
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Not a kernel function, treat it as a stub hypercall.
|
||
|
|
* Compute the physical address for __kvm_handle_stub_hvc
|
||
|
|
* (as the code lives in the idmaped page) and branch there.
|
||
|
|
* We hijack ip (r12) as a tmp register.
|
||
|
|
*/
|
||
|
|
push {r1}
|
||
|
|
ldr r1, =kimage_voffset
|
||
|
|
ldr r1, [r1]
|
||
|
|
ldr ip, =__kvm_handle_stub_hvc
|
||
|
|
sub ip, ip, r1
|
||
|
|
pop {r1}
|
||
|
|
|
||
|
|
bx ip
|
||
|
|
|
||
|
|
1:
|
||
|
|
/*
|
||
|
|
* Pushing r2 here is just a way of keeping the stack aligned to
|
||
|
|
* 8 bytes on any path that can trigger a HYP exception. Here,
|
||
|
|
* we may well be about to jump into the guest, and the guest
|
||
|
|
* exit would otherwise be badly decoded by our fancy
|
||
|
|
* "decode-exception-without-a-branch" code...
|
||
|
|
*/
|
||
|
|
push {r2, lr}
|
||
|
|
|
||
|
|
mov lr, r0
|
||
|
|
mov r0, r1
|
||
|
|
mov r1, r2
|
||
|
|
mov r2, r3
|
||
|
|
|
||
|
|
THUMB( orr lr, #1)
|
||
|
|
blx lr @ Call the HYP function
|
||
|
|
|
||
|
|
pop {r2, lr}
|
||
|
|
eret
|
||
|
|
|
||
|
|
guest_hvc_trap:
|
||
|
|
movw r2, #:lower16:ARM_SMCCC_ARCH_WORKAROUND_1
|
||
|
|
movt r2, #:upper16:ARM_SMCCC_ARCH_WORKAROUND_1
|
||
|
|
ldr r0, [sp] @ Guest's r0
|
||
|
|
teq r0, r2
|
||
|
|
bne guest_trap
|
||
|
|
add sp, sp, #12
|
||
|
|
@ Returns:
|
||
|
|
@ r0 = 0
|
||
|
|
@ r1 = HSR value (perfectly predictable)
|
||
|
|
@ r2 = ARM_SMCCC_ARCH_WORKAROUND_1
|
||
|
|
mov r0, #0
|
||
|
|
eret
|
||
|
|
|
||
|
|
guest_trap:
|
||
|
|
load_vcpu r0 @ Load VCPU pointer to r0
|
||
|
|
|
||
|
|
#ifdef CONFIG_VFPv3
|
||
|
|
@ Check for a VFP access
|
||
|
|
lsr r1, r1, #HSR_EC_SHIFT
|
||
|
|
cmp r1, #HSR_EC_CP_0_13
|
||
|
|
beq __vfp_guest_restore
|
||
|
|
#endif
|
||
|
|
|
||
|
|
mov r1, #ARM_EXCEPTION_HVC
|
||
|
|
b __guest_exit
|
||
|
|
|
||
|
|
hyp_irq:
|
||
|
|
push {r0, r1, r2}
|
||
|
|
mov r1, #ARM_EXCEPTION_IRQ
|
||
|
|
load_vcpu r0 @ Load VCPU pointer to r0
|
||
|
|
b __guest_exit
|
||
|
|
|
||
|
|
hyp_dabt:
|
||
|
|
push {r0, r1}
|
||
|
|
mrs r0, ELR_hyp
|
||
|
|
ldr r1, =abort_guest_exit_start
|
||
|
|
THUMB( add r1, r1, #1)
|
||
|
|
cmp r0, r1
|
||
|
|
ldrne r1, =abort_guest_exit_end
|
||
|
|
THUMB( addne r1, r1, #1)
|
||
|
|
cmpne r0, r1
|
||
|
|
pop {r0, r1}
|
||
|
|
bne __hyp_panic
|
||
|
|
|
||
|
|
orr r0, r0, #(1 << ARM_EXIT_WITH_ABORT_BIT)
|
||
|
|
eret
|
||
|
|
|
||
|
|
.ltorg
|
||
|
|
|
||
|
|
.popsection
|