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linux/arch/arm/kvm/hyp/switch.c
Christoffer Dall e329fb75d5 KVM: arm/arm64: Factor out VMID into struct kvm_vmid 
In preparation for nested virtualization where we are going to have more
than a single VMID per VM, let's factor out the VMID data into a
separate VMID data structure and change the VMID allocator to operate on
this new structure instead of using a struct kvm.

This also means that udate_vttbr now becomes update_vmid, and that the
vttbr itself is generated on the fly based on the stage 2 page table
base address and the vmid.

We cache the physical address of the pgd when allocating the pgd to
avoid doing the calculation on every entry to the guest and to avoid
calling into potentially non-hyp-mapped code from hyp/EL2.

If we wanted to merge the VMID allocator with the arm64 ASID allocator
at some point in the future, it should actually become easier to do that
after this patch.

Note that to avoid mapping the kvm_vmid_bits variable into hyp, we
simply forego the masking of the vmid value in kvm_get_vttbr and rely on
update_vmid to always assign a valid vmid value (within the supported
range).

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
[maz: minor cleanups]
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-02-19 21:05:35 +00:00

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/*
* Copyright (C) 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/jump_label.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
__asm__(".arch_extension virt");
/*
* Activate the traps, saving the host's fpexc register before
* overwriting it. We'll restore it on VM exit.
*/
static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu, u32 *fpexc_host)
{
u32 val;
/*
* We are about to set HCPTR.TCP10/11 to trap all floating point
* register accesses to HYP, however, the ARM ARM clearly states that
* traps are only taken to HYP if the operation would not otherwise
* trap to SVC. Therefore, always make sure that for 32-bit guests,
* we set FPEXC.EN to prevent traps to SVC, when setting the TCP bits.
*/
val = read_sysreg(VFP_FPEXC);
*fpexc_host = val;
if (!(val & FPEXC_EN)) {
write_sysreg(val | FPEXC_EN, VFP_FPEXC);
isb();
}
write_sysreg(vcpu->arch.hcr, HCR);
/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
write_sysreg(HSTR_T(15), HSTR);
write_sysreg(HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11), HCPTR);
val = read_sysreg(HDCR);
val |= HDCR_TPM | HDCR_TPMCR; /* trap performance monitors */
val |= HDCR_TDRA | HDCR_TDOSA | HDCR_TDA; /* trap debug regs */
write_sysreg(val, HDCR);
}
static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
{
u32 val;
/*
* If we pended a virtual abort, preserve it until it gets
* cleared. See B1.9.9 (Virtual Abort exception) for details,
* but the crucial bit is the zeroing of HCR.VA in the
* pseudocode.
*/
if (vcpu->arch.hcr & HCR_VA)
vcpu->arch.hcr = read_sysreg(HCR);
write_sysreg(0, HCR);
write_sysreg(0, HSTR);
val = read_sysreg(HDCR);
write_sysreg(val & ~(HDCR_TPM | HDCR_TPMCR), HDCR);
write_sysreg(0, HCPTR);
}
static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = kern_hyp_va(vcpu->kvm);
write_sysreg(kvm_get_vttbr(kvm), VTTBR);
write_sysreg(vcpu->arch.midr, VPIDR);
}
static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
{
write_sysreg(0, VTTBR);
write_sysreg(read_sysreg(MIDR), VPIDR);
}
static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
{
if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_save_state(vcpu);
__vgic_v3_deactivate_traps(vcpu);
}
}
static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
{
if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif)) {
__vgic_v3_activate_traps(vcpu);
__vgic_v3_restore_state(vcpu);
}
}
static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
{
u32 hsr = read_sysreg(HSR);
u8 ec = hsr >> HSR_EC_SHIFT;
u32 hpfar, far;
vcpu->arch.fault.hsr = hsr;
if (ec == HSR_EC_IABT)
far = read_sysreg(HIFAR);
else if (ec == HSR_EC_DABT)
far = read_sysreg(HDFAR);
else
return true;
/*
* B3.13.5 Reporting exceptions taken to the Non-secure PL2 mode:
*
* Abort on the stage 2 translation for a memory access from a
* Non-secure PL1 or PL0 mode:
*
* For any Access flag fault or Translation fault, and also for any
* Permission fault on the stage 2 translation of a memory access
* made as part of a translation table walk for a stage 1 translation,
* the HPFAR holds the IPA that caused the fault. Otherwise, the HPFAR
* is UNKNOWN.
*/
if (!(hsr & HSR_DABT_S1PTW) && (hsr & HSR_FSC_TYPE) == FSC_PERM) {
u64 par, tmp;
par = read_sysreg(PAR);
write_sysreg(far, ATS1CPR);
isb();
tmp = read_sysreg(PAR);
write_sysreg(par, PAR);
if (unlikely(tmp & 1))
return false; /* Translation failed, back to guest */
hpfar = ((tmp >> 12) & ((1UL << 28) - 1)) << 4;
} else {
hpfar = read_sysreg(HPFAR);
}
vcpu->arch.fault.hxfar = far;
vcpu->arch.fault.hpfar = hpfar;
return true;
}
int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
bool fp_enabled;
u64 exit_code;
u32 fpexc;
vcpu = kern_hyp_va(vcpu);
write_sysreg(vcpu, HTPIDR);
host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
guest_ctxt = &vcpu->arch.ctxt;
__sysreg_save_state(host_ctxt);
__banked_save_state(host_ctxt);
__activate_traps(vcpu, &fpexc);
__activate_vm(vcpu);
__vgic_restore_state(vcpu);
__timer_enable_traps(vcpu);
__sysreg_restore_state(guest_ctxt);
__banked_restore_state(guest_ctxt);
/* Jump in the fire! */
again:
exit_code = __guest_enter(vcpu, host_ctxt);
/* And we're baaack! */
if (exit_code == ARM_EXCEPTION_HVC && !__populate_fault_info(vcpu))
goto again;
fp_enabled = __vfp_enabled();
__banked_save_state(guest_ctxt);
__sysreg_save_state(guest_ctxt);
__timer_disable_traps(vcpu);
__vgic_save_state(vcpu);
__deactivate_traps(vcpu);
__deactivate_vm(vcpu);
__banked_restore_state(host_ctxt);
__sysreg_restore_state(host_ctxt);
if (fp_enabled) {
__vfp_save_state(&guest_ctxt->vfp);
__vfp_restore_state(&host_ctxt->vfp);
}
write_sysreg(fpexc, VFP_FPEXC);
return exit_code;
}
static const char * const __hyp_panic_string[] = {
[ARM_EXCEPTION_RESET] = "\nHYP panic: RST PC:%08x CPSR:%08x",
[ARM_EXCEPTION_UNDEFINED] = "\nHYP panic: UNDEF PC:%08x CPSR:%08x",
[ARM_EXCEPTION_SOFTWARE] = "\nHYP panic: SVC PC:%08x CPSR:%08x",
[ARM_EXCEPTION_PREF_ABORT] = "\nHYP panic: PABRT PC:%08x CPSR:%08x",
[ARM_EXCEPTION_DATA_ABORT] = "\nHYP panic: DABRT PC:%08x ADDR:%08x",
[ARM_EXCEPTION_IRQ] = "\nHYP panic: IRQ PC:%08x CPSR:%08x",
[ARM_EXCEPTION_FIQ] = "\nHYP panic: FIQ PC:%08x CPSR:%08x",
[ARM_EXCEPTION_HVC] = "\nHYP panic: HVC PC:%08x CPSR:%08x",
};
void __hyp_text __noreturn __hyp_panic(int cause)
{
u32 elr = read_special(ELR_hyp);
u32 val;
if (cause == ARM_EXCEPTION_DATA_ABORT)
val = read_sysreg(HDFAR);
else
val = read_special(SPSR);
if (read_sysreg(VTTBR)) {
struct kvm_vcpu *vcpu;
struct kvm_cpu_context *host_ctxt;
vcpu = (struct kvm_vcpu *)read_sysreg(HTPIDR);
host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
__timer_disable_traps(vcpu);
__deactivate_traps(vcpu);
__deactivate_vm(vcpu);
__banked_restore_state(host_ctxt);
__sysreg_restore_state(host_ctxt);
}
/* Call panic for real */
__hyp_do_panic(__hyp_panic_string[cause], elr, val);
unreachable();
}
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