Linux-libre 4.6.2-gnu

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
--- /dev/null
+++ 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();
+}