1 files changed, 217 insertions, 83 deletions

diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 7debb74843a0..e778eefcf214 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012,2013 - ARM Ltd
  * Author: Marc Zyngier <marc.zyngier@arm.com>
@@ -5,36 +6,34 @@
  * Derived from arch/arm/kvm/handle_exit.c:
  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
  * Author: Christoffer Dall <c.dall@virtualopensystems.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/kvm.h>
 #include <linux/kvm_host.h>
 
 #include <asm/esr.h>
+#include <asm/exception.h>
 #include <asm/kvm_asm.h>
-#include <asm/kvm_coproc.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_mmu.h>
-#include <asm/kvm_psci.h>
+#include <asm/debug-monitors.h>
+#include <asm/stacktrace/nvhe.h>
+#include <asm/traps.h>
+
+#include <kvm/arm_hypercalls.h>
 
 #define CREATE_TRACE_POINTS
-#include "trace.h"
+#include "trace_handle_exit.h"
 
-typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
+typedef int (*exit_handle_fn)(struct kvm_vcpu *);
 
-static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u64 esr)
+{
+	if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(NULL, esr))
+		kvm_inject_vabt(vcpu);
+}
+
+static int handle_hvc(struct kvm_vcpu *vcpu)
 {
 	int ret;
 
@@ -42,18 +41,27 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
 			    kvm_vcpu_hvc_get_imm(vcpu));
 	vcpu->stat.hvc_exit_stat++;
 
-	ret = kvm_psci_call(vcpu);
+	ret = kvm_hvc_call_handler(vcpu);
 	if (ret < 0) {
-		kvm_inject_undefined(vcpu);
+		vcpu_set_reg(vcpu, 0, ~0UL);
 		return 1;
 	}
 
 	return ret;
 }
 
-static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int handle_smc(struct kvm_vcpu *vcpu)
 {
-	kvm_inject_undefined(vcpu);
+	/*
+	 * "If an SMC instruction executed at Non-secure EL1 is
+	 * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
+	 * Trap exception, not a Secure Monitor Call exception [...]"
+	 *
+	 * We need to advance the PC after the trap, as it would
+	 * otherwise return to the same address...
+	 */
+	vcpu_set_reg(vcpu, 0, ~0UL);
+	kvm_incr_pc(vcpu);
 	return 1;
 }
 
@@ -61,7 +69,7 @@ static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  * Guest access to FP/ASIMD registers are routed to this handler only
  * when the system doesn't support FP/ASIMD.
  */
-static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int handle_no_fpsimd(struct kvm_vcpu *vcpu)
 {
 	kvm_inject_undefined(vcpu);
 	return 1;
@@ -73,26 +81,52 @@ static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run)
  *
  * @vcpu:	the vcpu pointer
  *
- * WFE: Yield the CPU and come back to this vcpu when the scheduler
+ * WFE[T]: Yield the CPU and come back to this vcpu when the scheduler
  * decides to.
- * WFI: Simply call kvm_vcpu_block(), which will halt execution of
+ * WFI: Simply call kvm_vcpu_halt(), which will halt execution of
  * world-switches and schedule other host processes until there is an
  * incoming IRQ or FIQ to the VM.
+ * WFIT: Same as WFI, with a timed wakeup implemented as a background timer
+ *
+ * WF{I,E}T can immediately return if the deadline has already expired.
  */
-static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int kvm_handle_wfx(struct kvm_vcpu *vcpu)
 {
-	if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
+	u64 esr = kvm_vcpu_get_esr(vcpu);
+
+	if (esr & ESR_ELx_WFx_ISS_WFE) {
 		trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
 		vcpu->stat.wfe_exit_stat++;
-		kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
 	} else {
 		trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
 		vcpu->stat.wfi_exit_stat++;
-		kvm_vcpu_block(vcpu);
-		kvm_clear_request(KVM_REQ_UNHALT, vcpu);
 	}
 
-	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+	if (esr & ESR_ELx_WFx_ISS_WFxT) {
+		if (esr & ESR_ELx_WFx_ISS_RV) {
+			u64 val, now;
+
+			now = kvm_arm_timer_get_reg(vcpu, KVM_REG_ARM_TIMER_CNT);
+			val = vcpu_get_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu));
+
+			if (now >= val)
+				goto out;
+		} else {
+			/* Treat WFxT as WFx if RN is invalid */
+			esr &= ~ESR_ELx_WFx_ISS_WFxT;
+		}
+	}
+
+	if (esr & ESR_ELx_WFx_ISS_WFE) {
+		kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
+	} else {
+		if (esr & ESR_ELx_WFx_ISS_WFxT)
+			vcpu_set_flag(vcpu, IN_WFIT);
+
+		kvm_vcpu_wfi(vcpu);
+	}
+out:
+	kvm_incr_pc(vcpu);
 
 	return 1;
 }
@@ -101,48 +135,63 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  * kvm_handle_guest_debug - handle a debug exception instruction
  *
  * @vcpu:	the vcpu pointer
- * @run:	access to the kvm_run structure for results
  *
  * We route all debug exceptions through the same handler. If both the
  * guest and host are using the same debug facilities it will be up to
  * userspace to re-inject the correct exception for guest delivery.
  *
- * @return: 0 (while setting run->exit_reason), -1 for error
+ * @return: 0 (while setting vcpu->run->exit_reason)
  */
-static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu)
 {
-	u32 hsr = kvm_vcpu_get_hsr(vcpu);
-	int ret = 0;
+	struct kvm_run *run = vcpu->run;
+	u64 esr = kvm_vcpu_get_esr(vcpu);
 
 	run->exit_reason = KVM_EXIT_DEBUG;
-	run->debug.arch.hsr = hsr;
+	run->debug.arch.hsr = lower_32_bits(esr);
+	run->debug.arch.hsr_high = upper_32_bits(esr);
+	run->flags = KVM_DEBUG_ARCH_HSR_HIGH_VALID;
 
-	switch (ESR_ELx_EC(hsr)) {
+	switch (ESR_ELx_EC(esr)) {
 	case ESR_ELx_EC_WATCHPT_LOW:
 		run->debug.arch.far = vcpu->arch.fault.far_el2;
-		/* fall through */
-	case ESR_ELx_EC_SOFTSTP_LOW:
-	case ESR_ELx_EC_BREAKPT_LOW:
-	case ESR_ELx_EC_BKPT32:
-	case ESR_ELx_EC_BRK64:
 		break;
-	default:
-		kvm_err("%s: un-handled case hsr: %#08x\n",
-			__func__, (unsigned int) hsr);
-		ret = -1;
+	case ESR_ELx_EC_SOFTSTP_LOW:
+		vcpu_clear_flag(vcpu, DBG_SS_ACTIVE_PENDING);
 		break;
 	}
 
-	return ret;
+	return 0;
 }
 
-static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu)
 {
-	u32 hsr = kvm_vcpu_get_hsr(vcpu);
+	u64 esr = kvm_vcpu_get_esr(vcpu);
 
-	kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n",
-		      hsr, esr_get_class_string(hsr));
+	kvm_pr_unimpl("Unknown exception class: esr: %#016llx -- %s\n",
+		      esr, esr_get_class_string(esr));
+
+	kvm_inject_undefined(vcpu);
+	return 1;
+}
+
+/*
+ * Guest access to SVE registers should be routed to this handler only
+ * when the system doesn't support SVE.
+ */
+static int handle_sve(struct kvm_vcpu *vcpu)
+{
+	kvm_inject_undefined(vcpu);
+	return 1;
+}
 
+/*
+ * Guest usage of a ptrauth instruction (which the guest EL1 did not turn into
+ * a NOP). If we get here, it is that we didn't fixup ptrauth on exit, and all
+ * that we can do is give the guest an UNDEF.
+ */
+static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu)
+{
 	kvm_inject_undefined(vcpu);
 	return 1;
 }
@@ -154,12 +203,14 @@ static exit_handle_fn arm_exit_handlers[] = {
 	[ESR_ELx_EC_CP15_64]	= kvm_handle_cp15_64,
 	[ESR_ELx_EC_CP14_MR]	= kvm_handle_cp14_32,
 	[ESR_ELx_EC_CP14_LS]	= kvm_handle_cp14_load_store,
+	[ESR_ELx_EC_CP10_ID]	= kvm_handle_cp10_id,
 	[ESR_ELx_EC_CP14_64]	= kvm_handle_cp14_64,
 	[ESR_ELx_EC_HVC32]	= handle_hvc,
 	[ESR_ELx_EC_SMC32]	= handle_smc,
 	[ESR_ELx_EC_HVC64]	= handle_hvc,
 	[ESR_ELx_EC_SMC64]	= handle_smc,
 	[ESR_ELx_EC_SYS64]	= kvm_handle_sys_reg,
+	[ESR_ELx_EC_SVE]	= handle_sve,
 	[ESR_ELx_EC_IABT_LOW]	= kvm_handle_guest_abort,
 	[ESR_ELx_EC_DABT_LOW]	= kvm_handle_guest_abort,
 	[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
@@ -168,40 +219,57 @@ static exit_handle_fn arm_exit_handlers[] = {
 	[ESR_ELx_EC_BKPT32]	= kvm_handle_guest_debug,
 	[ESR_ELx_EC_BRK64]	= kvm_handle_guest_debug,
 	[ESR_ELx_EC_FP_ASIMD]	= handle_no_fpsimd,
+	[ESR_ELx_EC_PAC]	= kvm_handle_ptrauth,
 };
 
 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 {
-	u32 hsr = kvm_vcpu_get_hsr(vcpu);
-	u8 hsr_ec = ESR_ELx_EC(hsr);
+	u64 esr = kvm_vcpu_get_esr(vcpu);
+	u8 esr_ec = ESR_ELx_EC(esr);
 
-	return arm_exit_handlers[hsr_ec];
+	return arm_exit_handlers[esr_ec];
+}
+
+/*
+ * We may be single-stepping an emulated instruction. If the emulation
+ * has been completed in the kernel, we can return to userspace with a
+ * KVM_EXIT_DEBUG, otherwise userspace needs to complete its
+ * emulation first.
+ */
+static int handle_trap_exceptions(struct kvm_vcpu *vcpu)
+{
+	int handled;
+
+	/*
+	 * See ARM ARM B1.14.1: "Hyp traps on instructions
+	 * that fail their condition code check"
+	 */
+	if (!kvm_condition_valid(vcpu)) {
+		kvm_incr_pc(vcpu);
+		handled = 1;
+	} else {
+		exit_handle_fn exit_handler;
+
+		exit_handler = kvm_get_exit_handler(vcpu);
+		handled = exit_handler(vcpu);
+	}
+
+	return handled;
 }
 
 /*
  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
  * proper exit to userspace.
  */
-int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
-		       int exception_index)
+int handle_exit(struct kvm_vcpu *vcpu, int exception_index)
 {
-	exit_handle_fn exit_handler;
+	struct kvm_run *run = vcpu->run;
 
 	if (ARM_SERROR_PENDING(exception_index)) {
-		u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu));
-
 		/*
-		 * HVC/SMC already have an adjusted PC, which we need
-		 * to correct in order to return to after having
-		 * injected the SError.
+		 * The SError is handled by handle_exit_early(). If the guest
+		 * survives it will re-execute the original instruction.
 		 */
-		if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 ||
-		    hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) {
-			u32 adj =  kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
-			*vcpu_pc(vcpu) -= adj;
-		}
-
-		kvm_inject_vabt(vcpu);
 		return 1;
 	}
 
@@ -211,28 +279,23 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	case ARM_EXCEPTION_IRQ:
 		return 1;
 	case ARM_EXCEPTION_EL1_SERROR:
-		kvm_inject_vabt(vcpu);
 		return 1;
 	case ARM_EXCEPTION_TRAP:
-		/*
-		 * See ARM ARM B1.14.1: "Hyp traps on instructions
-		 * that fail their condition code check"
-		 */
-		if (!kvm_condition_valid(vcpu)) {
-			kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
-			return 1;
-		}
-
-		exit_handler = kvm_get_exit_handler(vcpu);
-
-		return exit_handler(vcpu, run);
+		return handle_trap_exceptions(vcpu);
 	case ARM_EXCEPTION_HYP_GONE:
 		/*
 		 * EL2 has been reset to the hyp-stub. This happens when a guest
-		 * is pre-empted by kvm_reboot()'s shutdown call.
+		 * is pre-emptied by kvm_reboot()'s shutdown call.
 		 */
 		run->exit_reason = KVM_EXIT_FAIL_ENTRY;
 		return 0;
+	case ARM_EXCEPTION_IL:
+		/*
+		 * We attempted an illegal exception return.  Guest state must
+		 * have been corrupted somehow.  Give up.
+		 */
+		run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+		return -EINVAL;
 	default:
 		kvm_pr_unimpl("Unsupported exception type: %d",
 			      exception_index);
@@ -240,3 +303,74 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		return 0;
 	}
 }
+
+/* For exit types that need handling before we can be preempted */
+void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index)
+{
+	if (ARM_SERROR_PENDING(exception_index)) {
+		if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) {
+			u64 disr = kvm_vcpu_get_disr(vcpu);
+
+			kvm_handle_guest_serror(vcpu, disr_to_esr(disr));
+		} else {
+			kvm_inject_vabt(vcpu);
+		}
+
+		return;
+	}
+
+	exception_index = ARM_EXCEPTION_CODE(exception_index);
+
+	if (exception_index == ARM_EXCEPTION_EL1_SERROR)
+		kvm_handle_guest_serror(vcpu, kvm_vcpu_get_esr(vcpu));
+}
+
+void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
+					      u64 elr_virt, u64 elr_phys,
+					      u64 par, uintptr_t vcpu,
+					      u64 far, u64 hpfar) {
+	u64 elr_in_kimg = __phys_to_kimg(elr_phys);
+	u64 hyp_offset = elr_in_kimg - kaslr_offset() - elr_virt;
+	u64 mode = spsr & PSR_MODE_MASK;
+	u64 panic_addr = elr_virt + hyp_offset;
+
+	if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) {
+		kvm_err("Invalid host exception to nVHE hyp!\n");
+	} else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
+		   (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) {
+		const char *file = NULL;
+		unsigned int line = 0;
+
+		/* All hyp bugs, including warnings, are treated as fatal. */
+		if (!is_protected_kvm_enabled() ||
+		    IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {
+			struct bug_entry *bug = find_bug(elr_in_kimg);
+
+			if (bug)
+				bug_get_file_line(bug, &file, &line);
+		}
+
+		if (file)
+			kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
+		else
+			kvm_err("nVHE hyp BUG at: [<%016llx>] %pB!\n", panic_addr,
+					(void *)(panic_addr + kaslr_offset()));
+	} else {
+		kvm_err("nVHE hyp panic at: [<%016llx>] %pB!\n", panic_addr,
+				(void *)(panic_addr + kaslr_offset()));
+	}
+
+	/* Dump the nVHE hypervisor backtrace */
+	kvm_nvhe_dump_backtrace(hyp_offset);
+
+	/*
+	 * Hyp has panicked and we're going to handle that by panicking the
+	 * kernel. The kernel offset will be revealed in the panic so we're
+	 * also safe to reveal the hyp offset as a debugging aid for translating
+	 * hyp VAs to vmlinux addresses.
+	 */
+	kvm_err("Hyp Offset: 0x%llx\n", hyp_offset);
+
+	panic("HYP panic:\nPS:%08llx PC:%016llx ESR:%016llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%016lx\n",
+	      spsr, elr_virt, esr, far, hpfar, par, vcpu);
+}