Merge tag 'kvmarm-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm updates for 4.19

- Support for Group0 interrupts in guests
- Cache management optimizations for ARMv8.4 systems
- Userspace interface for RAS, allowing error retrival and injection
- Fault path optimization
- Emulated physical timer fixes
- Random cleanups

Documentation/virtual/kvm/api.txt

@@ -835,11 +835,13 @@ struct kvm_clock_data {
 
 Capability: KVM_CAP_VCPU_EVENTS
 Extended by: KVM_CAP_INTR_SHADOW
-Architectures: x86
-Type: vm ioctl
+Architectures: x86, arm, arm64
+Type: vcpu ioctl
 Parameters: struct kvm_vcpu_event (out)
 Returns: 0 on success, -1 on error
 
+X86:
+
 Gets currently pending exceptions, interrupts, and NMIs as well as related
 states of the vcpu.
 
@@ -881,15 +883,64 @@ Only two fields are defined in the flags field:
 - KVM_VCPUEVENT_VALID_SMM may be set in the flags field to signal that
   smi contains a valid state.
 
+ARM/ARM64:
+
+If the guest accesses a device that is being emulated by the host kernel in
+such a way that a real device would generate a physical SError, KVM may make
+a virtual SError pending for that VCPU. This system error interrupt remains
+pending until the guest takes the exception by unmasking PSTATE.A.
+
+Running the VCPU may cause it to take a pending SError, or make an access that
+causes an SError to become pending. The event's description is only valid while
+the VPCU is not running.
+
+This API provides a way to read and write the pending 'event' state that is not
+visible to the guest. To save, restore or migrate a VCPU the struct representing
+the state can be read then written using this GET/SET API, along with the other
+guest-visible registers. It is not possible to 'cancel' an SError that has been
+made pending.
+
+A device being emulated in user-space may also wish to generate an SError. To do
+this the events structure can be populated by user-space. The current state
+should be read first, to ensure no existing SError is pending. If an existing
+SError is pending, the architecture's 'Multiple SError interrupts' rules should
+be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and
+Serviceability (RAS) Specification").
+
+SError exceptions always have an ESR value. Some CPUs have the ability to
+specify what the virtual SError's ESR value should be. These systems will
+advertise KVM_CAP_ARM_SET_SERROR_ESR. In this case exception.has_esr will
+always have a non-zero value when read, and the agent making an SError pending
+should specify the ISS field in the lower 24 bits of exception.serror_esr. If
+the system supports KVM_CAP_ARM_SET_SERROR_ESR, but user-space sets the events
+with exception.has_esr as zero, KVM will choose an ESR.
+
+Specifying exception.has_esr on a system that does not support it will return
+-EINVAL. Setting anything other than the lower 24bits of exception.serror_esr
+will return -EINVAL.
+
+struct kvm_vcpu_events {
+	struct {
+		__u8 serror_pending;
+		__u8 serror_has_esr;
+		/* Align it to 8 bytes */
+		__u8 pad[6];
+		__u64 serror_esr;
+	} exception;
+	__u32 reserved[12];
+};
+
 4.32 KVM_SET_VCPU_EVENTS
 
 Capability: KVM_CAP_VCPU_EVENTS
 Extended by: KVM_CAP_INTR_SHADOW
-Architectures: x86
-Type: vm ioctl
+Architectures: x86, arm, arm64
+Type: vcpu ioctl
 Parameters: struct kvm_vcpu_event (in)
 Returns: 0 on success, -1 on error
 
+X86:
+
 Set pending exceptions, interrupts, and NMIs as well as related states of the
 vcpu.
 
@@ -910,6 +961,13 @@ shall be written into the VCPU.
 
 KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available.
 
+ARM/ARM64:
+
+Set the pending SError exception state for this VCPU. It is not possible to
+'cancel' an Serror that has been made pending.
+
+See KVM_GET_VCPU_EVENTS for the data structure.
+
 
 4.33 KVM_GET_DEBUGREGS
 
@@ -4690,3 +4748,17 @@ This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush
 hypercalls:
 HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx,
 HvFlushVirtualAddressList, HvFlushVirtualAddressListEx.
+
+8.19 KVM_CAP_ARM_SET_SERROR_ESR
+
+Architectures: arm, arm64
+
+This capability indicates that userspace can specify (via the
+KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it
+takes a virtual SError interrupt exception.
+If KVM advertises this capability, userspace can only specify the ISS field for
+the ESR syndrome. Other parts of the ESR, such as the EC are generated by the
+CPU when the exception is taken. If this virtual SError is taken to EL1 using
+AArch64, this value will be reported in the ISS field of ESR_ELx.
+
+See KVM_CAP_VCPU_EVENTS for more details.

Documentation/virtual/kvm/devices/arm-vgic-v3.txt

@@ -100,6 +100,14 @@ Groups:
     Note that distributor fields are not banked, but return the same value
     regardless of the mpidr used to access the register.
 
+    GICD_IIDR.Revision is updated when the KVM implementation is changed in a
+    way directly observable by the guest or userspace.  Userspace should read
+    GICD_IIDR from KVM and write back the read value to confirm its expected
+    behavior is aligned with the KVM implementation.  Userspace should set
+    GICD_IIDR before setting any other registers to ensure the expected
+    behavior.
+
+
     The GICD_STATUSR and GICR_STATUSR registers are architecturally defined such
     that a write of a clear bit has no effect, whereas a write with a set bit
     clears that value.  To allow userspace to freely set the values of these two

Documentation/virtual/kvm/devices/arm-vgic.txt

@@ -49,9 +49,15 @@ Groups:
     index is specified with the vcpu_index field.  Note that most distributor
     fields are not banked, but return the same value regardless of the
     vcpu_index used to access the register.
-  Limitations:
-    - Priorities are not implemented, and registers are RAZ/WI
-    - Currently only implemented for KVM_DEV_TYPE_ARM_VGIC_V2.
+
+    GICD_IIDR.Revision is updated when the KVM implementation of an emulated
+    GICv2 is changed in a way directly observable by the guest or userspace.
+    Userspace should read GICD_IIDR from KVM and write back the read value to
+    confirm its expected behavior is aligned with the KVM implementation.
+    Userspace should set GICD_IIDR before setting any other registers (both
+    KVM_DEV_ARM_VGIC_GRP_DIST_REGS and KVM_DEV_ARM_VGIC_GRP_CPU_REGS) to ensure
+    the expected behavior. Unless GICD_IIDR has been set from userspace, writes
+    to the interrupt group registers (GICD_IGROUPR) are ignored.
   Errors:
     -ENXIO: Getting or setting this register is not yet supported
     -EBUSY: One or more VCPUs are running
@@ -94,9 +100,6 @@ Groups:
     use the lower 5 bits to communicate with the KVM device and must shift the
     value left by 3 places to obtain the actual priority mask level.
 
-  Limitations:
-    - Priorities are not implemented, and registers are RAZ/WI
-    - Currently only implemented for KVM_DEV_TYPE_ARM_VGIC_V2.
   Errors:
     -ENXIO: Getting or setting this register is not yet supported
     -EBUSY: One or more VCPUs are running

arch/arm/include/asm/kvm_emulate.h

@@ -107,9 +107,19 @@ static inline unsigned long *vcpu_hcr(const struct kvm_vcpu *vcpu)
 	return (unsigned long *)&vcpu->arch.hcr;
 }
 
+static inline void vcpu_clear_wfe_traps(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.hcr &= ~HCR_TWE;
+}
+
+static inline void vcpu_set_wfe_traps(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.hcr |= HCR_TWE;
+}
+
 static inline bool vcpu_mode_is_32bit(const struct kvm_vcpu *vcpu)
 {
-	return 1;
+	return true;
 }
 
 static inline unsigned long *vcpu_pc(struct kvm_vcpu *vcpu)

arch/arm/include/asm/kvm_host.h

@@ -216,6 +216,11 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
 int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
 unsigned long kvm_call_hyp(void *hypfn, ...);
 void force_vm_exit(const cpumask_t *mask);
+int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events);
+
+int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events);
 
 #define KVM_ARCH_WANT_MMU_NOTIFIER
 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);

arch/arm/include/asm/kvm_mmu.h

@@ -75,17 +75,9 @@ phys_addr_t kvm_get_idmap_vector(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
-static inline void kvm_set_pmd(pmd_t *pmd, pmd_t new_pmd)
-{
-	*pmd = new_pmd;
-	dsb(ishst);
-}
-
-static inline void kvm_set_pte(pte_t *pte, pte_t new_pte)
-{
-	*pte = new_pte;
-	dsb(ishst);
-}
+#define kvm_mk_pmd(ptep)	__pmd(__pa(ptep) | PMD_TYPE_TABLE)
+#define kvm_mk_pud(pmdp)	__pud(__pa(pmdp) | PMD_TYPE_TABLE)
+#define kvm_mk_pgd(pudp)	({ BUILD_BUG(); 0; })
 
 static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
 {

arch/arm/include/uapi/asm/kvm.h

@@ -27,6 +27,7 @@
 #define __KVM_HAVE_GUEST_DEBUG
 #define __KVM_HAVE_IRQ_LINE
 #define __KVM_HAVE_READONLY_MEM
+#define __KVM_HAVE_VCPU_EVENTS
 
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 
@@ -125,6 +126,18 @@ struct kvm_sync_regs {
 struct kvm_arch_memory_slot {
 };
 
+/* for KVM_GET/SET_VCPU_EVENTS */
+struct kvm_vcpu_events {
+	struct {
+		__u8 serror_pending;
+		__u8 serror_has_esr;
+		/* Align it to 8 bytes */
+		__u8 pad[6];
+		__u64 serror_esr;
+	} exception;
+	__u32 reserved[12];
+};
+
 /* If you need to interpret the index values, here is the key: */
 #define KVM_REG_ARM_COPROC_MASK		0x000000000FFF0000
 #define KVM_REG_ARM_COPROC_SHIFT	16

arch/arm/kvm/coproc.c

@@ -246,6 +246,7 @@ static bool access_gic_sgi(struct kvm_vcpu *vcpu,
 			   const struct coproc_reg *r)
 {
 	u64 reg;
+	bool g1;
 
 	if (!p->is_write)
 		return read_from_write_only(vcpu, p);
@@ -253,7 +254,25 @@ static bool access_gic_sgi(struct kvm_vcpu *vcpu,
 	reg = (u64)*vcpu_reg(vcpu, p->Rt2) << 32;
 	reg |= *vcpu_reg(vcpu, p->Rt1) ;
 
-	vgic_v3_dispatch_sgi(vcpu, reg);
+	/*
+	 * In a system where GICD_CTLR.DS=1, a ICC_SGI0R access generates
+	 * Group0 SGIs only, while ICC_SGI1R can generate either group,
+	 * depending on the SGI configuration. ICC_ASGI1R is effectively
+	 * equivalent to ICC_SGI0R, as there is no "alternative" secure
+	 * group.
+	 */
+	switch (p->Op1) {
+	default:		/* Keep GCC quiet */
+	case 0:			/* ICC_SGI1R */
+		g1 = true;
+		break;
+	case 1:			/* ICC_ASGI1R */
+	case 2:			/* ICC_SGI0R */
+		g1 = false;
+		break;
+	}
+
+	vgic_v3_dispatch_sgi(vcpu, reg, g1);
 
 	return true;
 }
@@ -459,6 +478,10 @@ static const struct coproc_reg cp15_regs[] = {
 
 	/* ICC_SGI1R */
 	{ CRm64(12), Op1( 0), is64, access_gic_sgi},
+	/* ICC_ASGI1R */
+	{ CRm64(12), Op1( 1), is64, access_gic_sgi},
+	/* ICC_SGI0R */
+	{ CRm64(12), Op1( 2), is64, access_gic_sgi},
 
 	/* VBAR: swapped by interrupt.S. */
 	{ CRn(12), CRm( 0), Op1( 0), Op2( 0), is32,

arch/arm/kvm/guest.c

@@ -261,6 +261,29 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 	return -EINVAL;
 }
 
+
+int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events)
+{
+	events->exception.serror_pending = !!(*vcpu_hcr(vcpu) & HCR_VA);
+
+	return 0;
+}
+
+int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events)
+{
+	bool serror_pending = events->exception.serror_pending;
+	bool has_esr = events->exception.serror_has_esr;
+
+	if (serror_pending && has_esr)
+		return -EINVAL;
+	else if (serror_pending)
+		kvm_inject_vabt(vcpu);
+
+	return 0;
+}
+
 int __attribute_const__ kvm_target_cpu(void)
 {
 	switch (read_cpuid_part()) {

arch/arm64/include/asm/cpucaps.h

@@ -50,7 +50,8 @@
 #define ARM64_HW_DBM				29
 #define ARM64_SSBD				30
 #define ARM64_MISMATCHED_CACHE_TYPE		31
+#define ARM64_HAS_STAGE2_FWB			32
 
-#define ARM64_NCAPS				32
+#define ARM64_NCAPS				33
 
 #endif /* __ASM_CPUCAPS_H */

arch/arm64/include/asm/kvm_arm.h

@@ -23,6 +23,7 @@
 #include <asm/types.h>
 
 /* Hyp Configuration Register (HCR) bits */
+#define HCR_FWB		(UL(1) << 46)
 #define HCR_TEA		(UL(1) << 37)
 #define HCR_TERR	(UL(1) << 36)
 #define HCR_TLOR	(UL(1) << 35)

arch/arm64/include/asm/kvm_emulate.h

@@ -63,6 +63,8 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
 		/* trap error record accesses */
 		vcpu->arch.hcr_el2 |= HCR_TERR;
 	}
+	if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
+		vcpu->arch.hcr_el2 |= HCR_FWB;
 
 	if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features))
 		vcpu->arch.hcr_el2 &= ~HCR_RW;
@@ -81,6 +83,21 @@ static inline unsigned long *vcpu_hcr(struct kvm_vcpu *vcpu)
 	return (unsigned long *)&vcpu->arch.hcr_el2;
 }
 
+static inline void vcpu_clear_wfe_traps(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.hcr_el2 &= ~HCR_TWE;
+}
+
+static inline void vcpu_set_wfe_traps(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.hcr_el2 |= HCR_TWE;
+}
+
+static inline unsigned long vcpu_get_vsesr(struct kvm_vcpu *vcpu)
+{
+	return vcpu->arch.vsesr_el2;
+}
+
 static inline void vcpu_set_vsesr(struct kvm_vcpu *vcpu, u64 vsesr)
 {
 	vcpu->arch.vsesr_el2 = vsesr;

arch/arm64/include/asm/kvm_host.h

@@ -350,6 +350,11 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu);
 int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices);
 int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
 int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
+int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events);
+
+int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events);
 
 #define KVM_ARCH_WANT_MMU_NOTIFIER
 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
@@ -378,16 +383,23 @@ void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run,
 int kvm_perf_init(void);
 int kvm_perf_teardown(void);
 
+void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome);
+
 struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
 
-void __kvm_set_tpidr_el2(u64 tpidr_el2);
 DECLARE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
 
 static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 				       unsigned long hyp_stack_ptr,
 				       unsigned long vector_ptr)
 {
-	u64 tpidr_el2;
+	/*
+	 * Calculate the raw per-cpu offset without a translation from the
+	 * kernel's mapping to the linear mapping, and store it in tpidr_el2
+	 * so that we can use adr_l to access per-cpu variables in EL2.
+	 */
+	u64 tpidr_el2 = ((u64)this_cpu_ptr(&kvm_host_cpu_state) -
+			 (u64)kvm_ksym_ref(kvm_host_cpu_state));
 
 	/*
 	 * Call initialization code, and switch to the full blown HYP code.
@@ -396,17 +408,7 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 	 * cpus_have_const_cap() wrapper.
 	 */
 	BUG_ON(!static_branch_likely(&arm64_const_caps_ready));
-	__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
-
-	/*
-	 * Calculate the raw per-cpu offset without a translation from the
-	 * kernel's mapping to the linear mapping, and store it in tpidr_el2
-	 * so that we can use adr_l to access per-cpu variables in EL2.
-	 */
-	tpidr_el2 = (u64)this_cpu_ptr(&kvm_host_cpu_state)
-		- (u64)kvm_ksym_ref(kvm_host_cpu_state);
-
-	kvm_call_hyp(__kvm_set_tpidr_el2, tpidr_el2);
+	__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr, tpidr_el2);
 }
 
 static inline bool kvm_arch_check_sve_has_vhe(void)

arch/arm64/include/asm/kvm_mmu.h

@@ -169,8 +169,12 @@ phys_addr_t kvm_get_idmap_vector(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
-#define	kvm_set_pte(ptep, pte)		set_pte(ptep, pte)
-#define	kvm_set_pmd(pmdp, pmd)		set_pmd(pmdp, pmd)
+#define kvm_mk_pmd(ptep)					\
+	__pmd(__phys_to_pmd_val(__pa(ptep)) | PMD_TYPE_TABLE)
+#define kvm_mk_pud(pmdp)					\
+	__pud(__phys_to_pud_val(__pa(pmdp)) | PMD_TYPE_TABLE)
+#define kvm_mk_pgd(pudp)					\
+	__pgd(__phys_to_pgd_val(__pa(pudp)) | PUD_TYPE_TABLE)
 
 static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
 {
@@ -267,6 +271,15 @@ static inline void __clean_dcache_guest_page(kvm_pfn_t pfn, unsigned long size)
 {
 	void *va = page_address(pfn_to_page(pfn));
 
+	/*
+	 * With FWB, we ensure that the guest always accesses memory using
+	 * cacheable attributes, and we don't have to clean to PoC when
+	 * faulting in pages. Furthermore, FWB implies IDC, so cleaning to
+	 * PoU is not required either in this case.
+	 */
+	if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
+		return;
+
 	kvm_flush_dcache_to_poc(va, size);
 }
 
@@ -287,20 +300,26 @@ static inline void __invalidate_icache_guest_page(kvm_pfn_t pfn,
 
 static inline void __kvm_flush_dcache_pte(pte_t pte)
 {
-	struct page *page = pte_page(pte);
-	kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE);
+	if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) {
+		struct page *page = pte_page(pte);
+		kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE);
+	}
 }
 
 static inline void __kvm_flush_dcache_pmd(pmd_t pmd)
 {
-	struct page *page = pmd_page(pmd);
-	kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE);
+	if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) {
+		struct page *page = pmd_page(pmd);
+		kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE);
+	}
 }
 
 static inline void __kvm_flush_dcache_pud(pud_t pud)
 {
-	struct page *page = pud_page(pud);
-	kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE);
+	if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) {
+		struct page *page = pud_page(pud);
+		kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE);
+	}
 }
 
 #define kvm_virt_to_phys(x)		__pa_symbol(x)

arch/arm64/include/asm/memory.h

@@ -155,6 +155,13 @@
 #define MT_S2_NORMAL		0xf
 #define MT_S2_DEVICE_nGnRE	0x1
 
+/*
+ * Memory types for Stage-2 translation when ID_AA64MMFR2_EL1.FWB is 0001
+ * Stage-2 enforces Normal-WB and Device-nGnRE
+ */
+#define MT_S2_FWB_NORMAL	6
+#define MT_S2_FWB_DEVICE_nGnRE	1
+
 #ifdef CONFIG_ARM64_4K_PAGES
 #define IOREMAP_MAX_ORDER	(PUD_SHIFT)
 #else

arch/arm64/include/asm/pgtable-prot.h

@@ -67,8 +67,28 @@
 #define PAGE_HYP_RO		__pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN)
 #define PAGE_HYP_DEVICE		__pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
 
-#define PAGE_S2			__pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY | PTE_S2_XN)
-#define PAGE_S2_DEVICE		__pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN)
+#define PAGE_S2_MEMATTR(attr)						\
+	({								\
+		u64 __val;						\
+		if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))		\
+			__val = PTE_S2_MEMATTR(MT_S2_FWB_ ## attr);	\
+		else							\
+			__val = PTE_S2_MEMATTR(MT_S2_ ## attr);		\
+		__val;							\
+	 })
+
+#define PAGE_S2_XN							\
+	({								\
+		u64 __val;						\
+		if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC))		\
+			__val = 0;					\
+		else							\
+			__val = PTE_S2_XN;				\
+		__val;							\
+	})
+
+#define PAGE_S2			__pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PAGE_S2_XN)
+#define PAGE_S2_DEVICE		__pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PAGE_S2_XN)
 
 #define PAGE_NONE		__pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
 #define PAGE_SHARED		__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)

arch/arm64/include/asm/sysreg.h

@@ -314,6 +314,8 @@
 #define SYS_ICC_DIR_EL1			sys_reg(3, 0, 12, 11, 1)
 #define SYS_ICC_RPR_EL1			sys_reg(3, 0, 12, 11, 3)
 #define SYS_ICC_SGI1R_EL1		sys_reg(3, 0, 12, 11, 5)
+#define SYS_ICC_ASGI1R_EL1		sys_reg(3, 0, 12, 11, 6)
+#define SYS_ICC_SGI0R_EL1		sys_reg(3, 0, 12, 11, 7)
 #define SYS_ICC_IAR1_EL1		sys_reg(3, 0, 12, 12, 0)
 #define SYS_ICC_EOIR1_EL1		sys_reg(3, 0, 12, 12, 1)
 #define SYS_ICC_HPPIR1_EL1		sys_reg(3, 0, 12, 12, 2)
@@ -579,6 +581,7 @@
 #define ID_AA64MMFR1_VMIDBITS_16	2
 
 /* id_aa64mmfr2 */
+#define ID_AA64MMFR2_FWB_SHIFT		40
 #define ID_AA64MMFR2_AT_SHIFT		32
 #define ID_AA64MMFR2_LVA_SHIFT		16
 #define ID_AA64MMFR2_IESB_SHIFT		12

arch/arm64/include/uapi/asm/kvm.h

@@ -39,6 +39,7 @@
 #define __KVM_HAVE_GUEST_DEBUG
 #define __KVM_HAVE_IRQ_LINE
 #define __KVM_HAVE_READONLY_MEM
+#define __KVM_HAVE_VCPU_EVENTS
 
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 
@@ -154,6 +155,18 @@ struct kvm_sync_regs {
 struct kvm_arch_memory_slot {
 };
 
+/* for KVM_GET/SET_VCPU_EVENTS */
+struct kvm_vcpu_events {
+	struct {
+		__u8 serror_pending;
+		__u8 serror_has_esr;
+		/* Align it to 8 bytes */
+		__u8 pad[6];
+		__u64 serror_esr;
+	} exception;
+	__u32 reserved[12];
+};
+
 /* If you need to interpret the index values, here is the key: */
 #define KVM_REG_ARM_COPROC_MASK		0x000000000FFF0000
 #define KVM_REG_ARM_COPROC_SHIFT	16

arch/arm64/kernel/cpufeature.c

@@ -192,6 +192,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_IESB_SHIFT, 4, 0),
@@ -1026,6 +1027,14 @@ static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused)
 }
 #endif
 
+static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused)
+{
+	u64 val = read_sysreg_s(SYS_CLIDR_EL1);
+
+	/* Check that CLIDR_EL1.LOU{U,IS} are both 0 */
+	WARN_ON(val & (7 << 27 | 7 << 21));
+}
+
 static const struct arm64_cpu_capabilities arm64_features[] = {
 	{
 		.desc = "GIC system register CPU interface",
@@ -1182,6 +1191,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
 		.matches = has_cache_dic,
 	},
+	{
+		.desc = "Stage-2 Force Write-Back",
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.capability = ARM64_HAS_STAGE2_FWB,
+		.sys_reg = SYS_ID_AA64MMFR2_EL1,
+		.sign = FTR_UNSIGNED,
+		.field_pos = ID_AA64MMFR2_FWB_SHIFT,
+		.min_field_value = 1,
+		.matches = has_cpuid_feature,
+		.cpu_enable = cpu_has_fwb,
+	},
 #ifdef CONFIG_ARM64_HW_AFDBM
 	{
 		/*

arch/arm64/kvm/guest.c

@@ -289,6 +289,39 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 	return -EINVAL;
 }
 
+int __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events)
+{
+	events->exception.serror_pending = !!(vcpu->arch.hcr_el2 & HCR_VSE);
+	events->exception.serror_has_esr = cpus_have_const_cap(ARM64_HAS_RAS_EXTN);
+
+	if (events->exception.serror_pending && events->exception.serror_has_esr)
+		events->exception.serror_esr = vcpu_get_vsesr(vcpu);
+
+	return 0;
+}
+
+int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
+			      struct kvm_vcpu_events *events)
+{
+	bool serror_pending = events->exception.serror_pending;
+	bool has_esr = events->exception.serror_has_esr;
+
+	if (serror_pending && has_esr) {
+		if (!cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
+			return -EINVAL;
+
+		if (!((events->exception.serror_esr) & ~ESR_ELx_ISS_MASK))
+			kvm_set_sei_esr(vcpu, events->exception.serror_esr);
+		else
+			return -EINVAL;
+	} else if (serror_pending) {
+		kvm_inject_vabt(vcpu);
+	}
+
+	return 0;
+}
+
 int __attribute_const__ kvm_target_cpu(void)
 {
 	unsigned long implementor = read_cpuid_implementor();