linux_dsm_epyc7002/arch/arm64/kvm/hyp-init.S
Ard Biesheuvel e4c5a68510 arm64: KVM: use ID map with increased VA range if required
This patch modifies the HYP init code so it can deal with system
RAM residing at an offset which exceeds the reach of VA_BITS.

Like for EL1, this involves configuring an additional level of
translation for the ID map. However, in case of EL2, this implies
that all translations use the extra level, as we cannot seamlessly
switch between translation tables with different numbers of
translation levels.

So add an extra translation table at the root level. Since the
ID map and the runtime HYP map are guaranteed not to overlap, they
can share this root level, and we can essentially merge these two
tables into one.

Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-23 11:35:29 +00:00

146 lines
3.4 KiB
ArmAsm

/*
* Copyright (C) 2012,2013 - 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/assembler.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
#include <asm/pgtable-hwdef.h>
.text
.pushsection .hyp.idmap.text, "ax"
.align 11
ENTRY(__kvm_hyp_init)
ventry __invalid // Synchronous EL2t
ventry __invalid // IRQ EL2t
ventry __invalid // FIQ EL2t
ventry __invalid // Error EL2t
ventry __invalid // Synchronous EL2h
ventry __invalid // IRQ EL2h
ventry __invalid // FIQ EL2h
ventry __invalid // Error EL2h
ventry __do_hyp_init // Synchronous 64-bit EL1
ventry __invalid // IRQ 64-bit EL1
ventry __invalid // FIQ 64-bit EL1
ventry __invalid // Error 64-bit EL1
ventry __invalid // Synchronous 32-bit EL1
ventry __invalid // IRQ 32-bit EL1
ventry __invalid // FIQ 32-bit EL1
ventry __invalid // Error 32-bit EL1
__invalid:
b .
/*
* x0: HYP boot pgd
* x1: HYP pgd
* x2: HYP stack
* x3: HYP vectors
*/
__do_hyp_init:
msr ttbr0_el2, x0
mrs x4, tcr_el1
ldr x5, =TCR_EL2_MASK
and x4, x4, x5
ldr x5, =TCR_EL2_FLAGS
orr x4, x4, x5
#ifndef CONFIG_ARM64_VA_BITS_48
/*
* If we are running with VA_BITS < 48, we may be running with an extra
* level of translation in the ID map. This is only the case if system
* RAM is out of range for the currently configured page size and number
* of translation levels, in which case we will also need the extra
* level for the HYP ID map, or we won't be able to enable the EL2 MMU.
*
* However, at EL2, there is only one TTBR register, and we can't switch
* between translation tables *and* update TCR_EL2.T0SZ at the same
* time. Bottom line: we need the extra level in *both* our translation
* tables.
*
* So use the same T0SZ value we use for the ID map.
*/
ldr_l x5, idmap_t0sz
bfi x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
#endif
msr tcr_el2, x4
ldr x4, =VTCR_EL2_FLAGS
/*
* Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in
* VTCR_EL2.
*/
mrs x5, ID_AA64MMFR0_EL1
bfi x4, x5, #16, #3
msr vtcr_el2, x4
mrs x4, mair_el1
msr mair_el2, x4
isb
/* Invalidate the stale TLBs from Bootloader */
tlbi alle2
dsb sy
mrs x4, sctlr_el2
and x4, x4, #SCTLR_EL2_EE // preserve endianness of EL2
ldr x5, =SCTLR_EL2_FLAGS
orr x4, x4, x5
msr sctlr_el2, x4
isb
/* Skip the trampoline dance if we merged the boot and runtime PGDs */
cmp x0, x1
b.eq merged
/* MMU is now enabled. Get ready for the trampoline dance */
ldr x4, =TRAMPOLINE_VA
adr x5, target
bfi x4, x5, #0, #PAGE_SHIFT
br x4
target: /* We're now in the trampoline code, switch page tables */
msr ttbr0_el2, x1
isb
/* Invalidate the old TLBs */
tlbi alle2
dsb sy
merged:
/* Set the stack and new vectors */
kern_hyp_va x2
mov sp, x2
kern_hyp_va x3
msr vbar_el2, x3
/* Hello, World! */
eret
ENDPROC(__kvm_hyp_init)
.ltorg
.popsection