KVM/arm64 fixes for 6.5, part #2

- Fixes for the configuration of SVE/SME traps when hVHE mode is in use
 
  - Allow use of pKVM on systems with FF-A implementations that are v1.0
    compatible
 
  - Request/release percpu IRQs (arch timer, vGIC maintenance) correctly
    when pKVM is in use
 
  - Fix function prototype after __kvm_host_psci_cpu_entry() rename
 
  - Skip to the next instruction when emulating writes to TCR_EL1 on
    AmpereOne systems
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Merge tag 'kvmarm-fixes-6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.5, part #2

 - Fixes for the configuration of SVE/SME traps when hVHE mode is in use

 - Allow use of pKVM on systems with FF-A implementations that are v1.0
   compatible

 - Request/release percpu IRQs (arch timer, vGIC maintenance) correctly
   when pKVM is in use

 - Fix function prototype after __kvm_host_psci_cpu_entry() rename

 - Skip to the next instruction when emulating writes to TCR_EL1 on
   AmpereOne systems

arch/arm64/include/asm/el2_setup.h

@@ -31,6 +31,13 @@
 .Lskip_hcrx_\@:
 .endm
 
+/* Check if running in host at EL2 mode, i.e., (h)VHE. Jump to fail if not. */
+.macro __check_hvhe fail, tmp
+	mrs	\tmp, hcr_el2
+	and	\tmp, \tmp, #HCR_E2H
+	cbz	\tmp, \fail
+.endm
+
 /*
  * Allow Non-secure EL1 and EL0 to access physical timer and counter.
  * This is not necessary for VHE, since the host kernel runs in EL2,
@@ -43,9 +50,7 @@
  */
 .macro __init_el2_timers
 	mov	x0, #3				// Enable EL1 physical timers
-	mrs	x1, hcr_el2
+	__check_hvhe .LnVHE_\@, x1
-	and	x1, x1, #HCR_E2H
-	cbz	x1, .LnVHE_\@
 	lsl	x0, x0, #10
 .LnVHE_\@:
 	msr	cnthctl_el2, x0
@@ -139,15 +144,14 @@
 
 /* Coprocessor traps */
 .macro __init_el2_cptr
-	mrs	x1, hcr_el2
+	__check_hvhe .LnVHE_\@, x1
-	and	x1, x1, #HCR_E2H
-	cbz	x1, .LnVHE_\@
 	mov	x0, #(CPACR_EL1_FPEN_EL1EN | CPACR_EL1_FPEN_EL0EN)
-	b	.Lset_cptr_\@
+	msr	cpacr_el1, x0
+	b	.Lskip_set_cptr_\@
 .LnVHE_\@:
 	mov	x0, #0x33ff
-.Lset_cptr_\@:
 	msr	cptr_el2, x0			// Disable copro. traps to EL2
+.Lskip_set_cptr_\@:
 .endm
 
 /* Disable any fine grained traps */
@@ -268,19 +272,19 @@
 	check_override id_aa64pfr0, ID_AA64PFR0_EL1_SVE_SHIFT, .Linit_sve_\@, .Lskip_sve_\@, x1, x2
 
 .Linit_sve_\@:	/* SVE register access */
-	mrs	x0, cptr_el2			// Disable SVE traps
+	__check_hvhe .Lcptr_nvhe_\@, x1
-	mrs	x1, hcr_el2
-	and	x1, x1, #HCR_E2H
-	cbz	x1, .Lcptr_nvhe_\@
 
-	// VHE case
+	// (h)VHE case
+	mrs	x0, cpacr_el1			// Disable SVE traps
 	orr	x0, x0, #(CPACR_EL1_ZEN_EL1EN | CPACR_EL1_ZEN_EL0EN)
-	b	.Lset_cptr_\@
+	msr	cpacr_el1, x0
+	b	.Lskip_set_cptr_\@
 
 .Lcptr_nvhe_\@: // nVHE case
+	mrs	x0, cptr_el2			// Disable SVE traps
 	bic	x0, x0, #CPTR_EL2_TZ
-.Lset_cptr_\@:
 	msr	cptr_el2, x0
+.Lskip_set_cptr_\@:
 	isb
 	mov	x1, #ZCR_ELx_LEN_MASK		// SVE: Enable full vector
 	msr_s	SYS_ZCR_EL2, x1			// length for EL1.
@@ -289,9 +293,19 @@
 	check_override id_aa64pfr1, ID_AA64PFR1_EL1_SME_SHIFT, .Linit_sme_\@, .Lskip_sme_\@, x1, x2
 
 .Linit_sme_\@:	/* SME register access and priority mapping */
+	__check_hvhe .Lcptr_nvhe_sme_\@, x1
+
+	// (h)VHE case
+	mrs	x0, cpacr_el1			// Disable SME traps
+	orr	x0, x0, #(CPACR_EL1_SMEN_EL0EN | CPACR_EL1_SMEN_EL1EN)
+	msr	cpacr_el1, x0
+	b	.Lskip_set_cptr_sme_\@
+
+.Lcptr_nvhe_sme_\@: // nVHE case
 	mrs	x0, cptr_el2			// Disable SME traps
 	bic	x0, x0, #CPTR_EL2_TSM
 	msr	cptr_el2, x0
+.Lskip_set_cptr_sme_\@:
 	isb
 
 	mrs	x1, sctlr_el2

arch/arm64/include/asm/kvm_asm.h

@@ -278,7 +278,7 @@ asmlinkage void __noreturn hyp_panic_bad_stack(void);
 asmlinkage void kvm_unexpected_el2_exception(void);
 struct kvm_cpu_context;
 void handle_trap(struct kvm_cpu_context *host_ctxt);
-asmlinkage void __noreturn kvm_host_psci_cpu_entry(bool is_cpu_on);
+asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on);
 void __noreturn __pkvm_init_finalise(void);
 void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
 void kvm_patch_vector_branch(struct alt_instr *alt,

arch/arm64/include/asm/kvm_emulate.h

@@ -571,6 +571,14 @@ static inline bool vcpu_has_feature(struct kvm_vcpu *vcpu, int feature)
 	return test_bit(feature, vcpu->arch.features);
 }
 
+static __always_inline void kvm_write_cptr_el2(u64 val)
+{
+	if (has_vhe() || has_hvhe())
+		write_sysreg(val, cpacr_el1);
+	else
+		write_sysreg(val, cptr_el2);
+}
+
 static __always_inline u64 kvm_get_reset_cptr_el2(struct kvm_vcpu *vcpu)
 {
 	u64 val;
@@ -578,8 +586,16 @@ static __always_inline u64 kvm_get_reset_cptr_el2(struct kvm_vcpu *vcpu)
 	if (has_vhe()) {
 		val = (CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN |
 		       CPACR_EL1_ZEN_EL1EN);
+		if (cpus_have_final_cap(ARM64_SME))
+			val |= CPACR_EL1_SMEN_EL1EN;
 	} else if (has_hvhe()) {
 		val = (CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN);
+
+		if (!vcpu_has_sve(vcpu) ||
+		    (vcpu->arch.fp_state != FP_STATE_GUEST_OWNED))
+			val |= CPACR_EL1_ZEN_EL1EN | CPACR_EL1_ZEN_EL0EN;
+		if (cpus_have_final_cap(ARM64_SME))
+			val |= CPACR_EL1_SMEN_EL1EN | CPACR_EL1_SMEN_EL0EN;
 	} else {
 		val = CPTR_NVHE_EL2_RES1;
 
@@ -597,9 +613,6 @@ static __always_inline void kvm_reset_cptr_el2(struct kvm_vcpu *vcpu)
 {
 	u64 val = kvm_get_reset_cptr_el2(vcpu);
 
-	if (has_vhe() || has_hvhe())
+	kvm_write_cptr_el2(val);
-		write_sysreg(val, cpacr_el1);
-	else
-		write_sysreg(val, cptr_el2);
 }
 #endif /* __ARM64_KVM_EMULATE_H__ */

arch/arm64/kvm/arm.c

@@ -55,7 +55,7 @@ DECLARE_KVM_NVHE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
 
 static bool vgic_present, kvm_arm_initialised;
 
-static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);
+static DEFINE_PER_CPU(unsigned char, kvm_hyp_initialized);
 DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
 bool is_kvm_arm_initialised(void)
@@ -1864,18 +1864,24 @@ static void cpu_hyp_reinit(void)
 	cpu_hyp_init_features();
 }
 
-static void _kvm_arch_hardware_enable(void *discard)
+static void cpu_hyp_init(void *discard)
 {
-	if (!__this_cpu_read(kvm_arm_hardware_enabled)) {
+	if (!__this_cpu_read(kvm_hyp_initialized)) {
 		cpu_hyp_reinit();
-		__this_cpu_write(kvm_arm_hardware_enabled, 1);
+		__this_cpu_write(kvm_hyp_initialized, 1);
+	}
+}
+
+static void cpu_hyp_uninit(void *discard)
+{
+	if (__this_cpu_read(kvm_hyp_initialized)) {
+		cpu_hyp_reset();
+		__this_cpu_write(kvm_hyp_initialized, 0);
 	}
 }
 
 int kvm_arch_hardware_enable(void)
 {
-	int was_enabled;
-
 	/*
 	 * Most calls to this function are made with migration
 	 * disabled, but not with preemption disabled. The former is
@@ -1884,36 +1890,23 @@ int kvm_arch_hardware_enable(void)
 	 */
 	preempt_disable();
 
-	was_enabled = __this_cpu_read(kvm_arm_hardware_enabled);
+	cpu_hyp_init(NULL);
-	_kvm_arch_hardware_enable(NULL);
 
-	if (!was_enabled) {
 	kvm_vgic_cpu_up();
 	kvm_timer_cpu_up();
-	}
 
 	preempt_enable();
 
 	return 0;
 }
 
-static void _kvm_arch_hardware_disable(void *discard)
-{
-	if (__this_cpu_read(kvm_arm_hardware_enabled)) {
-		cpu_hyp_reset();
-		__this_cpu_write(kvm_arm_hardware_enabled, 0);
-	}
-}
-
 void kvm_arch_hardware_disable(void)
 {
-	if (__this_cpu_read(kvm_arm_hardware_enabled)) {
 	kvm_timer_cpu_down();
 	kvm_vgic_cpu_down();
-	}
 
 	if (!is_protected_kvm_enabled())
-		_kvm_arch_hardware_disable(NULL);
+		cpu_hyp_uninit(NULL);
 }
 
 #ifdef CONFIG_CPU_PM
@@ -1922,16 +1915,16 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
 				    void *v)
 {
 	/*
-	 * kvm_arm_hardware_enabled is left with its old value over
+	 * kvm_hyp_initialized is left with its old value over
 	 * PM_ENTER->PM_EXIT. It is used to indicate PM_EXIT should
 	 * re-enable hyp.
 	 */
 	switch (cmd) {
 	case CPU_PM_ENTER:
-		if (__this_cpu_read(kvm_arm_hardware_enabled))
+		if (__this_cpu_read(kvm_hyp_initialized))
 			/*
-			 * don't update kvm_arm_hardware_enabled here
+			 * don't update kvm_hyp_initialized here
-			 * so that the hardware will be re-enabled
+			 * so that the hyp will be re-enabled
 			 * when we resume. See below.
 			 */
 			cpu_hyp_reset();
@@ -1939,8 +1932,8 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
 		return NOTIFY_OK;
 	case CPU_PM_ENTER_FAILED:
 	case CPU_PM_EXIT:
-		if (__this_cpu_read(kvm_arm_hardware_enabled))
+		if (__this_cpu_read(kvm_hyp_initialized))
-			/* The hardware was enabled before suspend. */
+			/* The hyp was enabled before suspend. */
 			cpu_hyp_reinit();
 
 		return NOTIFY_OK;
@@ -2021,7 +2014,7 @@ static int __init init_subsystems(void)
 	/*
 	 * Enable hardware so that subsystem initialisation can access EL2.
 	 */
-	on_each_cpu(_kvm_arch_hardware_enable, NULL, 1);
+	on_each_cpu(cpu_hyp_init, NULL, 1);
 
 	/*
 	 * Register CPU lower-power notifier
@@ -2059,7 +2052,7 @@ out:
 		hyp_cpu_pm_exit();
 
 	if (err || !is_protected_kvm_enabled())
-		on_each_cpu(_kvm_arch_hardware_disable, NULL, 1);
+		on_each_cpu(cpu_hyp_uninit, NULL, 1);
 
 	return err;
 }
@@ -2097,7 +2090,7 @@ static int __init do_pkvm_init(u32 hyp_va_bits)
 	 * The stub hypercalls are now disabled, so set our local flag to
 	 * prevent a later re-init attempt in kvm_arch_hardware_enable().
 	 */
-	__this_cpu_write(kvm_arm_hardware_enabled, 1);
+	__this_cpu_write(kvm_hyp_initialized, 1);
 	preempt_enable();
 
 	return ret;

arch/arm64/kvm/hyp/include/hyp/switch.h

@@ -457,6 +457,7 @@ static bool handle_ampere1_tcr(struct kvm_vcpu *vcpu)
 	 */
 	val &= ~(TCR_HD | TCR_HA);
 	write_sysreg_el1(val, SYS_TCR);
+	__kvm_skip_instr(vcpu);
 	return true;
 }
 

arch/arm64/kvm/hyp/nvhe/ffa.c

@@ -705,7 +705,20 @@ int hyp_ffa_init(void *pages)
 	if (res.a0 == FFA_RET_NOT_SUPPORTED)
 		return 0;
 
-	if (res.a0 != FFA_VERSION_1_0)
+	/*
+	 * Firmware returns the maximum supported version of the FF-A
+	 * implementation. Check that the returned version is
+	 * backwards-compatible with the hyp according to the rules in DEN0077A
+	 * v1.1 REL0 13.2.1.
+	 *
+	 * Of course, things are never simple when dealing with firmware. v1.1
+	 * broke ABI with v1.0 on several structures, which is itself
+	 * incompatible with the aforementioned versioning scheme. The
+	 * expectation is that v1.x implementations that do not support the v1.0
+	 * ABI return NOT_SUPPORTED rather than a version number, according to
+	 * DEN0077A v1.1 REL0 18.6.4.
+	 */
+	if (FFA_MAJOR_VERSION(res.a0) != 1)
 		return -EOPNOTSUPP;
 
 	arm_smccc_1_1_smc(FFA_ID_GET, 0, 0, 0, 0, 0, 0, 0, &res);

arch/arm64/kvm/hyp/nvhe/switch.c

@@ -63,7 +63,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
 		__activate_traps_fpsimd32(vcpu);
 	}
 
-	write_sysreg(val, cptr_el2);
+	kvm_write_cptr_el2(val);
 	write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el2);
 
 	if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {