Merge tag 'kvm-arm-fixes-for-5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master

KVM/ARM fixes for 5.0:

- Fix the way we reset vcpus, plugging the race that could happen on VHE
- Fix potentially inconsistent group setting for private interrupts
- Don't generate UNDEF when LORegion feature is present
- Relax the restriction on using stage2 PUD huge mapping
- Turn some spinlocks into raw_spinlocks to help RT compliance

5 files changed, 101 insertions, 20 deletions

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7732d0ba4e60..da3fc7324d68 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -48,6 +48,7 @@
 #define KVM_REQ_SLEEP \
 	KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
 #define KVM_REQ_IRQ_PENDING	KVM_ARCH_REQ(1)
+#define KVM_REQ_VCPU_RESET	KVM_ARCH_REQ(2)
 
 DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
@@ -208,6 +209,13 @@ struct kvm_cpu_context {
 
 typedef struct kvm_cpu_context kvm_cpu_context_t;
 
+struct vcpu_reset_state {
+	unsigned long	pc;
+	unsigned long	r0;
+	bool		be;
+	bool		reset;
+};
+
 struct kvm_vcpu_arch {
 	struct kvm_cpu_context ctxt;
 
@@ -297,6 +305,9 @@ struct kvm_vcpu_arch {
 	/* Virtual SError ESR to restore when HCR_EL2.VSE is set */
 	u64 vsesr_el2;
 
+	/* Additional reset state */
+	struct vcpu_reset_state	reset_state;
+
 	/* True when deferrable sysregs are loaded on the physical CPU,
 	 * see kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs. */
 	bool sysregs_loaded_on_cpu;
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index b0b1478094b4..421ebf6f7086 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -23,6 +23,7 @@
 #include <kvm/arm_psci.h>
 
 #include <asm/cpufeature.h>
+#include <asm/kprobes.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_host.h>
@@ -107,6 +108,7 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu)
 
 	write_sysreg(kvm_get_hyp_vector(), vbar_el1);
 }
+NOKPROBE_SYMBOL(activate_traps_vhe);
 
 static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)
 {
@@ -154,6 +156,7 @@ static void deactivate_traps_vhe(void)
 	write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1);
 	write_sysreg(vectors, vbar_el1);
 }
+NOKPROBE_SYMBOL(deactivate_traps_vhe);
 
 static void __hyp_text __deactivate_traps_nvhe(void)
 {
@@ -513,6 +516,7 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 
 	return exit_code;
 }
+NOKPROBE_SYMBOL(kvm_vcpu_run_vhe);
 
 /* Switch to the guest for legacy non-VHE systems */
 int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
@@ -620,6 +624,7 @@ static void __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par,
 	      read_sysreg_el2(esr),   read_sysreg_el2(far),
 	      read_sysreg(hpfar_el2), par, vcpu);
 }
+NOKPROBE_SYMBOL(__hyp_call_panic_vhe);
 
 void __hyp_text __noreturn hyp_panic(struct kvm_cpu_context *host_ctxt)
 {
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 68d6f7c3b237..b426e2cf973c 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -18,6 +18,7 @@
 #include <linux/compiler.h>
 #include <linux/kvm_host.h>
 
+#include <asm/kprobes.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
@@ -98,12 +99,14 @@ void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_save_common_state(ctxt);
 }
+NOKPROBE_SYMBOL(sysreg_save_host_state_vhe);
 
 void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_save_common_state(ctxt);
 	__sysreg_save_el2_return_state(ctxt);
 }
+NOKPROBE_SYMBOL(sysreg_save_guest_state_vhe);
 
 static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
 {
@@ -188,12 +191,14 @@ void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_restore_common_state(ctxt);
 }
+NOKPROBE_SYMBOL(sysreg_restore_host_state_vhe);
 
 void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt)
 {
 	__sysreg_restore_common_state(ctxt);
 	__sysreg_restore_el2_return_state(ctxt);
 }
+NOKPROBE_SYMBOL(sysreg_restore_guest_state_vhe);
 
 void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 {
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index b72a3dd56204..f16a5f8ff2b4 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -32,6 +32,7 @@
 #include <asm/kvm_arm.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_coproc.h>
+#include <asm/kvm_emulate.h>
 #include <asm/kvm_mmu.h>
 
 /* Maximum phys_shift supported for any VM on this host */
@@ -105,16 +106,33 @@ int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext)
  * This function finds the right table above and sets the registers on
  * the virtual CPU struct to their architecturally defined reset
  * values.
+ *
+ * Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT
+ * ioctl or as part of handling a request issued by another VCPU in the PSCI
+ * handling code.  In the first case, the VCPU will not be loaded, and in the
+ * second case the VCPU will be loaded.  Because this function operates purely
+ * on the memory-backed valus of system registers, we want to do a full put if
+ * we were loaded (handling a request) and load the values back at the end of
+ * the function.  Otherwise we leave the state alone.  In both cases, we
+ * disable preemption around the vcpu reset as we would otherwise race with
+ * preempt notifiers which also call put/load.
  */
 int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 {
 	const struct kvm_regs *cpu_reset;
+	int ret = -EINVAL;
+	bool loaded;
+
+	preempt_disable();
+	loaded = (vcpu->cpu != -1);
+	if (loaded)
+		kvm_arch_vcpu_put(vcpu);
 
 	switch (vcpu->arch.target) {
 	default:
 		if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
 			if (!cpu_has_32bit_el1())
-				return -EINVAL;
+				goto out;
 			cpu_reset = &default_regs_reset32;
 		} else {
 			cpu_reset = &default_regs_reset;
@@ -129,6 +147,29 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	/* Reset system registers */
 	kvm_reset_sys_regs(vcpu);
 
+	/*
+	 * Additional reset state handling that PSCI may have imposed on us.
+	 * Must be done after all the sys_reg reset.
+	 */
+	if (vcpu->arch.reset_state.reset) {
+		unsigned long target_pc = vcpu->arch.reset_state.pc;
+
+		/* Gracefully handle Thumb2 entry point */
+		if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
+			target_pc &= ~1UL;
+			vcpu_set_thumb(vcpu);
+		}
+
+		/* Propagate caller endianness */
+		if (vcpu->arch.reset_state.be)
+			kvm_vcpu_set_be(vcpu);
+
+		*vcpu_pc(vcpu) = target_pc;
+		vcpu_set_reg(vcpu, 0, vcpu->arch.reset_state.r0);
+
+		vcpu->arch.reset_state.reset = false;
+	}
+
 	/* Reset PMU */
 	kvm_pmu_vcpu_reset(vcpu);
 
@@ -137,7 +178,12 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 		vcpu->arch.workaround_flags |= VCPU_WORKAROUND_2_FLAG;
 
 	/* Reset timer */
-	return kvm_timer_vcpu_reset(vcpu);
+	ret = kvm_timer_vcpu_reset(vcpu);
+out:
+	if (loaded)
+		kvm_arch_vcpu_load(vcpu, smp_processor_id());
+	preempt_enable();
+	return ret;
 }
 
 void kvm_set_ipa_limit(void)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index e3e37228ae4e..c936aa40c3f4 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -314,12 +314,29 @@ static bool trap_raz_wi(struct kvm_vcpu *vcpu,
 		return read_zero(vcpu, p);
 }
 
-static bool trap_undef(struct kvm_vcpu *vcpu,
-		       struct sys_reg_params *p,
-		       const struct sys_reg_desc *r)
+/*
+ * ARMv8.1 mandates at least a trivial LORegion implementation, where all the
+ * RW registers are RES0 (which we can implement as RAZ/WI). On an ARMv8.0
+ * system, these registers should UNDEF. LORID_EL1 being a RO register, we
+ * treat it separately.
+ */
+static bool trap_loregion(struct kvm_vcpu *vcpu,
+			  struct sys_reg_params *p,
+			  const struct sys_reg_desc *r)
 {
-	kvm_inject_undefined(vcpu);
-	return false;
+	u64 val = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
+	u32 sr = sys_reg((u32)r->Op0, (u32)r->Op1,
+			 (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
+
+	if (!(val & (0xfUL << ID_AA64MMFR1_LOR_SHIFT))) {
+		kvm_inject_undefined(vcpu);
+		return false;
+	}
+
+	if (p->is_write && sr == SYS_LORID_EL1)
+		return write_to_read_only(vcpu, p, r);
+
+	return trap_raz_wi(vcpu, p, r);
 }
 
 static bool trap_oslsr_el1(struct kvm_vcpu *vcpu,
@@ -1048,11 +1065,6 @@ static u64 read_id_reg(struct sys_reg_desc const *r, bool raz)
 		if (val & ptrauth_mask)
 			kvm_debug("ptrauth unsupported for guests, suppressing\n");
 		val &= ~ptrauth_mask;
-	} else if (id == SYS_ID_AA64MMFR1_EL1) {
-		if (val & (0xfUL << ID_AA64MMFR1_LOR_SHIFT))
-			kvm_debug("LORegions unsupported for guests, suppressing\n");
-
-		val &= ~(0xfUL << ID_AA64MMFR1_LOR_SHIFT);
 	}
 
 	return val;
@@ -1338,11 +1350,11 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_MAIR_EL1), access_vm_reg, reset_unknown, MAIR_EL1 },
 	{ SYS_DESC(SYS_AMAIR_EL1), access_vm_reg, reset_amair_el1, AMAIR_EL1 },
 
-	{ SYS_DESC(SYS_LORSA_EL1), trap_undef },
-	{ SYS_DESC(SYS_LOREA_EL1), trap_undef },
-	{ SYS_DESC(SYS_LORN_EL1), trap_undef },
-	{ SYS_DESC(SYS_LORC_EL1), trap_undef },
-	{ SYS_DESC(SYS_LORID_EL1), trap_undef },
+	{ SYS_DESC(SYS_LORSA_EL1), trap_loregion },
+	{ SYS_DESC(SYS_LOREA_EL1), trap_loregion },
+	{ SYS_DESC(SYS_LORN_EL1), trap_loregion },
+	{ SYS_DESC(SYS_LORC_EL1), trap_loregion },
+	{ SYS_DESC(SYS_LORID_EL1), trap_loregion },
 
 	{ SYS_DESC(SYS_VBAR_EL1), NULL, reset_val, VBAR_EL1, 0 },
 	{ SYS_DESC(SYS_DISR_EL1), NULL, reset_val, DISR_EL1, 0 },
@@ -2596,7 +2608,9 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
 	table = get_target_table(vcpu->arch.target, true, &num);
 	reset_sys_reg_descs(vcpu, table, num);
 
-	for (num = 1; num < NR_SYS_REGS; num++)
-		if (__vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
-			panic("Didn't reset __vcpu_sys_reg(%zi)", num);
+	for (num = 1; num < NR_SYS_REGS; num++) {
+		if (WARN(__vcpu_sys_reg(vcpu, num) == 0x4242424242424242,
+			 "Didn't reset __vcpu_sys_reg(%zi)\n", num))
+			break;
+	}
 }