Merge branch kvm-arm64/fpsimd-tracking into kvmarm-master/next

* kvm-arm64/fpsimd-tracking:
  : .
  : Simplify the handling of both the FP/SIMD and SVE state by
  : removing the need for mapping the thread at EL2, and by
  : dropping the tracking of the host's SVE state which is
  : always invalid by construction.
  : .
  arm64/fpsimd: Document the use of TIF_FOREIGN_FPSTATE by KVM
  KVM: arm64: Stop mapping current thread_info at EL2
  KVM: arm64: Introduce flag shadowing TIF_FOREIGN_FPSTATE
  KVM: arm64: Remove unused __sve_save_state
  KVM: arm64: Get rid of host SVE tracking/saving
  KVM: arm64: Reorder vcpu flag definitions

Signed-off-by: Marc Zyngier <maz@kernel.org>

6 files changed, 21 insertions, 64 deletions

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index c79d8e5230bc..9b745d2bc89a 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -856,6 +856,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		}
 
 		kvm_arm_setup_debug(vcpu);
+		kvm_arch_vcpu_ctxflush_fp(vcpu);
 
 		/**************************************************************
 		 * Enter the guest
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index 62c0d78da7be..5526d79c7b47 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -7,7 +7,6 @@
  */
 #include <linux/irqflags.h>
 #include <linux/sched.h>
-#include <linux/thread_info.h>
 #include <linux/kvm_host.h>
 #include <asm/fpsimd.h>
 #include <asm/kvm_asm.h>
@@ -28,24 +27,13 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
 {
 	int ret;
 
-	struct thread_info *ti = &current->thread_info;
 	struct user_fpsimd_state *fpsimd = &current->thread.uw.fpsimd_state;
 
-	/*
-	 * Make sure the host task thread flags and fpsimd state are
-	 * visible to hyp:
-	 */
-	ret = create_hyp_mappings(ti, ti + 1, PAGE_HYP);
-	if (ret)
-		goto error;
-
+	/* Make sure the host task fpsimd state is visible to hyp: */
 	ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP);
-	if (ret)
-		goto error;
+	if (!ret)
+		vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
 
-	vcpu->arch.host_thread_info = kern_hyp_va(ti);
-	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
-error:
 	return ret;
 }
 
@@ -55,26 +43,27 @@ error:
  *
  * Here, we just set the correct metadata to indicate that the FPSIMD
  * state in the cpu regs (if any) belongs to current on the host.
- *
- * TIF_SVE is backed up here, since it may get clobbered with guest state.
- * This flag is restored by kvm_arch_vcpu_put_fp(vcpu).
  */
 void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
 {
 	BUG_ON(!current->mm);
+	BUG_ON(test_thread_flag(TIF_SVE));
 
-	vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
-			      KVM_ARM64_HOST_SVE_IN_USE |
-			      KVM_ARM64_HOST_SVE_ENABLED);
+	vcpu->arch.flags &= ~KVM_ARM64_FP_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;
 }
 
+void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu)
+{
+	if (test_thread_flag(TIF_FOREIGN_FPSTATE))
+		vcpu->arch.flags |= KVM_ARM64_FP_FOREIGN_FPSTATE;
+	else
+		vcpu->arch.flags &= ~KVM_ARM64_FP_FOREIGN_FPSTATE;
+}
+
 /*
  * If the guest FPSIMD state was loaded, update the host's context
  * tracking data mark the CPU FPSIMD regs as dirty and belonging to vcpu
@@ -104,13 +93,11 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
 void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
 {
 	unsigned long flags;
-	bool host_has_sve = system_supports_sve();
-	bool guest_has_sve = vcpu_has_sve(vcpu);
 
 	local_irq_save(flags);
 
 	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
-		if (guest_has_sve) {
+		if (vcpu_has_sve(vcpu)) {
 			__vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);
 
 			/* Restore the VL that was saved when bound to the CPU */
@@ -120,7 +107,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
 		}
 
 		fpsimd_save_and_flush_cpu_state();
-	} else if (has_vhe() && host_has_sve) {
+	} else if (has_vhe() && 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
@@ -134,8 +121,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
 			sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0);
 	}
 
-	update_thread_flag(TIF_SVE,
-			   vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
+	update_thread_flag(TIF_SVE, 0);
 
 	local_irq_restore(flags);
 }
diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
index e950875e31ce..61e6f3ba7b7d 100644
--- a/arch/arm64/kvm/hyp/fpsimd.S
+++ b/arch/arm64/kvm/hyp/fpsimd.S
@@ -25,9 +25,3 @@ SYM_FUNC_START(__sve_restore_state)
 	sve_load 0, x1, x2, 3
 	ret
 SYM_FUNC_END(__sve_restore_state)
-
-SYM_FUNC_START(__sve_save_state)
-	mov	x2, #1
-	sve_save 0, x1, x2, 3
-	ret
-SYM_FUNC_END(__sve_save_state)
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 7a0af1d39303..11e8580f2fdc 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -29,7 +29,6 @@
 #include <asm/fpsimd.h>
 #include <asm/debug-monitors.h>
 #include <asm/processor.h>
-#include <asm/thread_info.h>
 
 struct kvm_exception_table_entry {
 	int insn, fixup;
@@ -49,7 +48,7 @@ static inline bool update_fp_enabled(struct kvm_vcpu *vcpu)
 	 * trap the accesses.
 	 */
 	if (!system_supports_fpsimd() ||
-	    vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE)
+	    vcpu->arch.flags & KVM_ARM64_FP_FOREIGN_FPSTATE)
 		vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
 				      KVM_ARM64_FP_HOST);
 
@@ -143,16 +142,6 @@ static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
 	return __get_fault_info(vcpu->arch.fault.esr_el2, &vcpu->arch.fault);
 }
 
-static inline void __hyp_sve_save_host(struct kvm_vcpu *vcpu)
-{
-	struct thread_struct *thread;
-
-	thread = container_of(vcpu->arch.host_fpsimd_state, struct thread_struct,
-			      uw.fpsimd_state);
-
-	__sve_save_state(sve_pffr(thread), &vcpu->arch.host_fpsimd_state->fpsr);
-}
-
 static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
 {
 	sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, SYS_ZCR_EL2);
@@ -169,21 +158,14 @@ static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
  */
 static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
-	bool sve_guest, sve_host;
+	bool sve_guest;
 	u8 esr_ec;
 	u64 reg;
 
 	if (!system_supports_fpsimd())
 		return false;
 
-	if (system_supports_sve()) {
-		sve_guest = vcpu_has_sve(vcpu);
-		sve_host = vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE;
-	} else {
-		sve_guest = false;
-		sve_host = false;
-	}
-
+	sve_guest = vcpu_has_sve(vcpu);
 	esr_ec = kvm_vcpu_trap_get_class(vcpu);
 
 	/* Don't handle SVE traps for non-SVE vcpus here: */
@@ -207,11 +189,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
 	isb();
 
 	if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
-		if (sve_host)
-			__hyp_sve_save_host(vcpu);
-		else
-			__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
-
+		__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
 		vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
 	}
 
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index c0e3fed26d93..329c706af39f 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -25,7 +25,6 @@
 #include <asm/fpsimd.h>
 #include <asm/debug-monitors.h>
 #include <asm/processor.h>
-#include <asm/thread_info.h>
 
 #include <nvhe/fixed_config.h>
 #include <nvhe/mem_protect.h>
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index 5a2cb5d9bc4b..1d162b9c78bf 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -24,7 +24,6 @@
 #include <asm/fpsimd.h>
 #include <asm/debug-monitors.h>
 #include <asm/processor.h>
-#include <asm/thread_info.h>
 
 /* VHE specific context */
 DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);