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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
commitd635711daa98be86d4c7fd01499c34f566b54ccb (patch)
treeaa5cc3760a27c3d57146498cb82fa549547de06c /arch/arm/kvm/hyp/switch.c
parentc91265cd0efb83778f015b4d4b1129bd2cfd075e (diff)
Linux-libre 4.6.2-gnu
Diffstat (limited to 'arch/arm/kvm/hyp/switch.c')
-rw-r--r--arch/arm/kvm/hyp/switch.c232
1 files changed, 232 insertions, 0 deletions
diff --git a/arch/arm/kvm/hyp/switch.c b/arch/arm/kvm/hyp/switch.c
new file mode 100644
index 000000000..b13caa90c
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+++ b/arch/arm/kvm/hyp/switch.c
@@ -0,0 +1,232 @@
+/*
+ * 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 <asm/kvm_asm.h>
+#include <asm/kvm_hyp.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 | vcpu->arch.irq_lines, 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);
+ write_sysreg(val | HDCR_TPM | HDCR_TPMCR, HDCR);
+}
+
+static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
+{
+ u32 val;
+
+ 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->arch.vttbr, 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)
+{
+ __vgic_v2_save_state(vcpu);
+}
+
+static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
+{
+ __vgic_v2_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;
+}
+
+static int __hyp_text __guest_run(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_restore_state(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_save_state(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;
+}
+
+__alias(__guest_run) int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+
+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);
+ __deactivate_traps(vcpu);
+ __deactivate_vm(vcpu);
+ __sysreg_restore_state(host_ctxt);
+ }
+
+ /* Call panic for real */
+ __hyp_do_panic(__hyp_panic_string[cause], elr, val);
+
+ unreachable();
+}