Merge tag 'kvmarm-fixes-for-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm

KVM/arm fixes for 4.18, take #1

- Lazy FPSIMD switching fixes
- Really disable compat ioctls on architectures that don't want it
- Disable compat on arm64 (it was never implemented...)
- Rely on architectural requirements for GICV on GICv3
- Detect bad alignments in unmap_stage2_range

arch/arm64/include/asm/kvm_host.h

@@ -306,6 +306,7 @@ struct kvm_vcpu_arch {
 #define KVM_ARM64_FP_ENABLED		(1 << 1) /* guest FP regs loaded */
 #define KVM_ARM64_FP_HOST		(1 << 2) /* host FP regs loaded */
 #define KVM_ARM64_HOST_SVE_IN_USE	(1 << 3) /* backup for host TIF_SVE */
+#define KVM_ARM64_HOST_SVE_ENABLED	(1 << 4) /* SVE enabled for EL0 */
 
 #define vcpu_gp_regs(v)		(&(v)->arch.ctxt.gp_regs)
 

arch/arm64/include/asm/sysreg.h

@@ -728,6 +728,17 @@ asm(
 	asm volatile("msr_s " __stringify(r) ", %x0" : : "rZ" (__val));	\
 } while (0)
 
+/*
+ * Modify bits in a sysreg. Bits in the clear mask are zeroed, then bits in the
+ * set mask are set. Other bits are left as-is.
+ */
+#define sysreg_clear_set(sysreg, clear, set) do {			\
+	u64 __scs_val = read_sysreg(sysreg);				\
+	u64 __scs_new = (__scs_val & ~(u64)(clear)) | (set);		\
+	if (__scs_new != __scs_val)					\
+		write_sysreg(__scs_new, sysreg);			\
+} while (0)
+
 static inline void config_sctlr_el1(u32 clear, u32 set)
 {
 	u32 val;

arch/arm64/kvm/fpsimd.c

@@ -5,13 +5,14 @@
  * Copyright 2018 Arm Limited
  * Author: Dave Martin <Dave.Martin@arm.com>
  */
-#include <linux/bottom_half.h>
+#include <linux/irqflags.h>
 #include <linux/sched.h>
 #include <linux/thread_info.h>
 #include <linux/kvm_host.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_host.h>
 #include <asm/kvm_mmu.h>
+#include <asm/sysreg.h>
 
 /*
  * Called on entry to KVM_RUN unless this vcpu previously ran at least
@@ -61,10 +62,16 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
 {
 	BUG_ON(!current->mm);
 
-	vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | KVM_ARM64_HOST_SVE_IN_USE);
+	vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
+			      KVM_ARM64_HOST_SVE_IN_USE |
+			      KVM_ARM64_HOST_SVE_ENABLED);
 	vcpu->arch.flags |= KVM_ARM64_FP_HOST;
+
 	if (test_thread_flag(TIF_SVE))
 		vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE;
+
+	if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)
+		vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED;
 }
 
 /*
@@ -92,19 +99,30 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
  */
 void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
 {
-	local_bh_disable();
+	unsigned long flags;
 
-	update_thread_flag(TIF_SVE,
-			   vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
+	local_irq_save(flags);
 
 	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
 		/* Clean guest FP state to memory and invalidate cpu view */
 		fpsimd_save();
 		fpsimd_flush_cpu_state();
-	} else if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {
-		/* Ensure user trap controls are correctly restored */
-		fpsimd_bind_task_to_cpu();
+	} else if (system_supports_sve()) {
+		/*
+		 * The FPSIMD/SVE state in the CPU has not been touched, and we
+		 * have SVE (and VHE): CPACR_EL1 (alias CPTR_EL2) has been
+		 * reset to CPACR_EL1_DEFAULT by the Hyp code, disabling SVE
+		 * for EL0.  To avoid spurious traps, restore the trap state
+		 * seen by kvm_arch_vcpu_load_fp():
+		 */
+		if (vcpu->arch.flags & KVM_ARM64_HOST_SVE_ENABLED)
+			sysreg_clear_set(CPACR_EL1, 0, CPACR_EL1_ZEN_EL0EN);
+		else
+			sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0);
 	}
 
-	local_bh_enable();
+	update_thread_flag(TIF_SVE,
+			   vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
+
+	local_irq_restore(flags);
 }

virt/kvm/Kconfig

@@ -47,7 +47,7 @@ config KVM_GENERIC_DIRTYLOG_READ_PROTECT
 
 config KVM_COMPAT
        def_bool y
-       depends on KVM && COMPAT && !S390
+       depends on KVM && COMPAT && !(S390 || ARM64)
 
 config HAVE_KVM_IRQ_BYPASS
        bool

virt/kvm/arm/mmu.c

@@ -297,6 +297,8 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
 	phys_addr_t next;
 
 	assert_spin_locked(&kvm->mmu_lock);
+	WARN_ON(size & ~PAGE_MASK);
+
 	pgd = kvm->arch.pgd + stage2_pgd_index(addr);
 	do {
 		/*

virt/kvm/arm/vgic/vgic-v3.c

@@ -617,11 +617,6 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
 		pr_warn("GICV physical address 0x%llx not page aligned\n",
 			(unsigned long long)info->vcpu.start);
 		kvm_vgic_global_state.vcpu_base = 0;
-	} else if (!PAGE_ALIGNED(resource_size(&info->vcpu))) {
-		pr_warn("GICV size 0x%llx not a multiple of page size 0x%lx\n",
-			(unsigned long long)resource_size(&info->vcpu),
-			PAGE_SIZE);
-		kvm_vgic_global_state.vcpu_base = 0;
 	} else {
 		kvm_vgic_global_state.vcpu_base = info->vcpu.start;
 		kvm_vgic_global_state.can_emulate_gicv2 = true;

virt/kvm/kvm_main.c

@@ -116,6 +116,11 @@ static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
 #ifdef CONFIG_KVM_COMPAT
 static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
 				  unsigned long arg);
+#define KVM_COMPAT(c)	.compat_ioctl	= (c)
+#else
+static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
+				unsigned long arg) { return -EINVAL; }
+#define KVM_COMPAT(c)	.compat_ioctl	= kvm_no_compat_ioctl
 #endif
 static int hardware_enable_all(void);
 static void hardware_disable_all(void);
@@ -2396,11 +2401,9 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp)
 static struct file_operations kvm_vcpu_fops = {
 	.release        = kvm_vcpu_release,
 	.unlocked_ioctl = kvm_vcpu_ioctl,
-#ifdef CONFIG_KVM_COMPAT
-	.compat_ioctl   = kvm_vcpu_compat_ioctl,
-#endif
 	.mmap           = kvm_vcpu_mmap,
 	.llseek		= noop_llseek,
+	KVM_COMPAT(kvm_vcpu_compat_ioctl),
 };
 
 /*
@@ -2824,10 +2827,8 @@ static int kvm_device_release(struct inode *inode, struct file *filp)
 
 static const struct file_operations kvm_device_fops = {
 	.unlocked_ioctl = kvm_device_ioctl,
-#ifdef CONFIG_KVM_COMPAT
-	.compat_ioctl = kvm_device_ioctl,
-#endif
 	.release = kvm_device_release,
+	KVM_COMPAT(kvm_device_ioctl),
 };
 
 struct kvm_device *kvm_device_from_filp(struct file *filp)
@@ -3165,10 +3166,8 @@ static long kvm_vm_compat_ioctl(struct file *filp,
 static struct file_operations kvm_vm_fops = {
 	.release        = kvm_vm_release,
 	.unlocked_ioctl = kvm_vm_ioctl,
-#ifdef CONFIG_KVM_COMPAT
-	.compat_ioctl   = kvm_vm_compat_ioctl,
-#endif
 	.llseek		= noop_llseek,
+	KVM_COMPAT(kvm_vm_compat_ioctl),
 };
 
 static int kvm_dev_ioctl_create_vm(unsigned long type)
@@ -3259,8 +3258,8 @@ static long kvm_dev_ioctl(struct file *filp,
 
 static struct file_operations kvm_chardev_ops = {
 	.unlocked_ioctl = kvm_dev_ioctl,
-	.compat_ioctl   = kvm_dev_ioctl,
 	.llseek		= noop_llseek,
+	KVM_COMPAT(kvm_dev_ioctl),
 };
 
 static struct miscdevice kvm_dev = {