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linux-next/arch/arm64/kvm/hyp/sysreg-sr.c
Marc Zyngier 9bc03f1df3 arm64: KVM: Cleanup tpidr_el2 init on non-VHE 
When running on a non-VHE system, we initialize tpidr_el2 to
contain the per-CPU offset required to reach per-cpu variables.

Actually, we initialize it twice: the first time as part of the
EL2 initialization, by copying tpidr_el1 into its el2 counterpart,
and another time by calling into __kvm_set_tpidr_el2.

It turns out that the first part is wrong, as it includes the
distance between the kernel mapping and the linear mapping, while
EL2 only cares about the linear mapping. This was the last vestige
of the first per-cpu use of tpidr_el2 that came in with SDEI.
The only caller then was hyp_panic(), and its now using the
pc-relative get_host_ctxt() stuff, instead of kimage addresses
from the literal pool.

It is not a big deal, as we override it straight away, but it is
slightly confusing. In order to clear said confusion, let's
set this directly as part of the hyp-init code, and drop the
ad-hoc HYP helper.

Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-07-21 16:02:17 +01:00

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/*
* Copyright (C) 2012-2015 - 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/compiler.h>
#include <linux/kvm_host.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
/*
* Non-VHE: Both host and guest must save everything.
*
* VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and pstate,
* which are handled as part of the el2 return state) on every switch.
* tpidr_el0 and tpidrro_el0 only need to be switched when going
* to host userspace or a different VCPU. EL1 registers only need to be
* switched when potentially going to run a different VCPU. The latter two
* classes are handled as part of kvm_arch_vcpu_load and kvm_arch_vcpu_put.
*/
static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
{
ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
/*
* The host arm64 Linux uses sp_el0 to point to 'current' and it must
* therefore be saved/restored on every entry/exit to/from the guest.
*/
ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
}
static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
{
ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
}
static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
{
ctxt->sys_regs[MPIDR_EL1] = read_sysreg(vmpidr_el2);
ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1);
ctxt->sys_regs[SCTLR_EL1] = read_sysreg_el1(sctlr);
ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
ctxt->sys_regs[CPACR_EL1] = read_sysreg_el1(cpacr);
ctxt->sys_regs[TTBR0_EL1] = read_sysreg_el1(ttbr0);
ctxt->sys_regs[TTBR1_EL1] = read_sysreg_el1(ttbr1);
ctxt->sys_regs[TCR_EL1] = read_sysreg_el1(tcr);
ctxt->sys_regs[ESR_EL1] = read_sysreg_el1(esr);
ctxt->sys_regs[AFSR0_EL1] = read_sysreg_el1(afsr0);
ctxt->sys_regs[AFSR1_EL1] = read_sysreg_el1(afsr1);
ctxt->sys_regs[FAR_EL1] = read_sysreg_el1(far);
ctxt->sys_regs[MAIR_EL1] = read_sysreg_el1(mair);
ctxt->sys_regs[VBAR_EL1] = read_sysreg_el1(vbar);
ctxt->sys_regs[CONTEXTIDR_EL1] = read_sysreg_el1(contextidr);
ctxt->sys_regs[AMAIR_EL1] = read_sysreg_el1(amair);
ctxt->sys_regs[CNTKCTL_EL1] = read_sysreg_el1(cntkctl);
ctxt->sys_regs[PAR_EL1] = read_sysreg(par_el1);
ctxt->sys_regs[TPIDR_EL1] = read_sysreg(tpidr_el1);
ctxt->gp_regs.sp_el1 = read_sysreg(sp_el1);
ctxt->gp_regs.elr_el1 = read_sysreg_el1(elr);
ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(spsr);
}
static void __hyp_text __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
{
ctxt->gp_regs.regs.pc = read_sysreg_el2(elr);
ctxt->gp_regs.regs.pstate = read_sysreg_el2(spsr);
if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
ctxt->sys_regs[DISR_EL1] = read_sysreg_s(SYS_VDISR_EL2);
}
void __hyp_text __sysreg_save_state_nvhe(struct kvm_cpu_context *ctxt)
{
__sysreg_save_el1_state(ctxt);
__sysreg_save_common_state(ctxt);
__sysreg_save_user_state(ctxt);
__sysreg_save_el2_return_state(ctxt);
}
void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt)
{
__sysreg_save_common_state(ctxt);
}
void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt)
{
__sysreg_save_common_state(ctxt);
__sysreg_save_el2_return_state(ctxt);
}
static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
{
write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
/*
* The host arm64 Linux uses sp_el0 to point to 'current' and it must
* therefore be saved/restored on every entry/exit to/from the guest.
*/
write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
}
static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
{
write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
}
static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
{
write_sysreg(ctxt->sys_regs[MPIDR_EL1], vmpidr_el2);
write_sysreg(ctxt->sys_regs[CSSELR_EL1], csselr_el1);
write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1], sctlr);
write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
write_sysreg_el1(ctxt->sys_regs[CPACR_EL1], cpacr);
write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1], ttbr0);
write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1], ttbr1);
write_sysreg_el1(ctxt->sys_regs[TCR_EL1], tcr);
write_sysreg_el1(ctxt->sys_regs[ESR_EL1], esr);
write_sysreg_el1(ctxt->sys_regs[AFSR0_EL1], afsr0);
write_sysreg_el1(ctxt->sys_regs[AFSR1_EL1], afsr1);
write_sysreg_el1(ctxt->sys_regs[FAR_EL1], far);
write_sysreg_el1(ctxt->sys_regs[MAIR_EL1], mair);
write_sysreg_el1(ctxt->sys_regs[VBAR_EL1], vbar);
write_sysreg_el1(ctxt->sys_regs[CONTEXTIDR_EL1],contextidr);
write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1], amair);
write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1], cntkctl);
write_sysreg(ctxt->sys_regs[PAR_EL1], par_el1);
write_sysreg(ctxt->sys_regs[TPIDR_EL1], tpidr_el1);
write_sysreg(ctxt->gp_regs.sp_el1, sp_el1);
write_sysreg_el1(ctxt->gp_regs.elr_el1, elr);
write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],spsr);
}
static void __hyp_text
__sysreg_restore_el2_return_state(struct kvm_cpu_context *ctxt)
{
write_sysreg_el2(ctxt->gp_regs.regs.pc, elr);
write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);
}
void __hyp_text __sysreg_restore_state_nvhe(struct kvm_cpu_context *ctxt)
{
__sysreg_restore_el1_state(ctxt);
__sysreg_restore_common_state(ctxt);
__sysreg_restore_user_state(ctxt);
__sysreg_restore_el2_return_state(ctxt);
}
void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt)
{
__sysreg_restore_common_state(ctxt);
}
void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt)
{
__sysreg_restore_common_state(ctxt);
__sysreg_restore_el2_return_state(ctxt);
}
void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
{
u64 *spsr, *sysreg;
if (!vcpu_el1_is_32bit(vcpu))
return;
spsr = vcpu->arch.ctxt.gp_regs.spsr;
sysreg = vcpu->arch.ctxt.sys_regs;
spsr[KVM_SPSR_ABT] = read_sysreg(spsr_abt);
spsr[KVM_SPSR_UND] = read_sysreg(spsr_und);
spsr[KVM_SPSR_IRQ] = read_sysreg(spsr_irq);
spsr[KVM_SPSR_FIQ] = read_sysreg(spsr_fiq);
sysreg[DACR32_EL2] = read_sysreg(dacr32_el2);
sysreg[IFSR32_EL2] = read_sysreg(ifsr32_el2);
if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
sysreg[DBGVCR32_EL2] = read_sysreg(dbgvcr32_el2);
}
void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
{
u64 *spsr, *sysreg;
if (!vcpu_el1_is_32bit(vcpu))
return;
spsr = vcpu->arch.ctxt.gp_regs.spsr;
sysreg = vcpu->arch.ctxt.sys_regs;
write_sysreg(spsr[KVM_SPSR_ABT], spsr_abt);
write_sysreg(spsr[KVM_SPSR_UND], spsr_und);
write_sysreg(spsr[KVM_SPSR_IRQ], spsr_irq);
write_sysreg(spsr[KVM_SPSR_FIQ], spsr_fiq);
write_sysreg(sysreg[DACR32_EL2], dacr32_el2);
write_sysreg(sysreg[IFSR32_EL2], ifsr32_el2);
if (has_vhe() || vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)
write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
}
/**
* kvm_vcpu_load_sysregs - Load guest system registers to the physical CPU
*
* @vcpu: The VCPU pointer
*
* Load system registers that do not affect the host's execution, for
* example EL1 system registers on a VHE system where the host kernel
* runs at EL2. This function is called from KVM's vcpu_load() function
* and loading system register state early avoids having to load them on
* every entry to the VM.
*/
void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
if (!has_vhe())
return;
__sysreg_save_user_state(host_ctxt);
/*
* Load guest EL1 and user state
*
* We must restore the 32-bit state before the sysregs, thanks
* to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
*/
__sysreg32_restore_state(vcpu);
__sysreg_restore_user_state(guest_ctxt);
__sysreg_restore_el1_state(guest_ctxt);
vcpu->arch.sysregs_loaded_on_cpu = true;
activate_traps_vhe_load(vcpu);
}
/**
* kvm_vcpu_put_sysregs - Restore host system registers to the physical CPU
*
* @vcpu: The VCPU pointer
*
* Save guest system registers that do not affect the host's execution, for
* example EL1 system registers on a VHE system where the host kernel
* runs at EL2. This function is called from KVM's vcpu_put() function
* and deferring saving system register state until we're no longer running the
* VCPU avoids having to save them on every exit from the VM.
*/
void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context;
struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
if (!has_vhe())
return;
deactivate_traps_vhe_put();
__sysreg_save_el1_state(guest_ctxt);
__sysreg_save_user_state(guest_ctxt);
__sysreg32_save_state(vcpu);
/* Restore host user state */
__sysreg_restore_user_state(host_ctxt);
vcpu->arch.sysregs_loaded_on_cpu = false;
}
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