[PATCH v4 10/14] KVM: arm64: Share all userspace hardened thread data with the hypervisor

[Mark Brown]

As part of the lazy FPSIMD state transitioning done by the hypervisor we
currently share the userpsace FPSIMD state in thread->uw.fpsimd_state with
the host. Since this struct is non-extensible userspace ABI we have to keep
the definition as is but the addition of FPMR in the 2023 dpISA means that
we will want to share more storage with the host. To facilitate this
refactor the current code to share the entire thread->uw rather than just
the one field.

The large number of references to fpsimd_state make it very inconvenient
to add an additional wrapper struct.

Signed-off-by: Mark Brown <broonie at kernel.org>
---
 arch/arm64/include/asm/kvm_host.h       |  3 ++-
 arch/arm64/include/asm/processor.h      |  2 +-
 arch/arm64/kvm/fpsimd.c                 | 13 ++++++-------
 arch/arm64/kvm/hyp/include/hyp/switch.h |  2 +-
 arch/arm64/kvm/hyp/nvhe/hyp-main.c      |  4 ++--
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7993694a54af..c4fdcc94d733 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -27,6 +27,7 @@
 #include <asm/fpsimd.h>
 #include <asm/kvm.h>
 #include <asm/kvm_asm.h>
+#include <asm/processor.h>
 #include <asm/vncr_mapping.h>
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -601,7 +602,7 @@ struct kvm_vcpu_arch {
 	struct kvm_guest_debug_arch vcpu_debug_state;
 	struct kvm_guest_debug_arch external_debug_state;
 
-	struct user_fpsimd_state *host_fpsimd_state;	/* hyp VA */
+	struct thread_struct_uw *host_uw;	/* hyp VA */
 	struct task_struct *parent_task;
 
 	struct {
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index b453c66d3fae..544baa57f9b9 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -152,7 +152,7 @@ struct thread_struct {
 	 * Maintainers must ensure manually that this contains no
 	 * implicit padding.
 	 */
-	struct {
+	struct thread_struct_uw {
 		unsigned long	tp_value;	/* TLS register */
 		unsigned long	tp2_value;
 		unsigned long	fpmr;
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index e3e611e30e91..6cf22cd8f020 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -17,13 +17,13 @@
 void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
 {
 	struct task_struct *p = vcpu->arch.parent_task;
-	struct user_fpsimd_state *fpsimd;
+	struct thread_struct_uw *uw;
 
 	if (!is_protected_kvm_enabled() || !p)
 		return;
 
-	fpsimd = &p->thread.uw.fpsimd_state;
-	kvm_unshare_hyp(fpsimd, fpsimd + 1);
+	uw = &p->thread.uw;
+	kvm_unshare_hyp(uw, uw + 1);
 	put_task_struct(p);
 }
 
@@ -39,17 +39,16 @@ void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
 int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
 {
 	int ret;
-
-	struct user_fpsimd_state *fpsimd = &current->thread.uw.fpsimd_state;
+	struct thread_struct_uw *uw = &current->thread.uw;
 
 	kvm_vcpu_unshare_task_fp(vcpu);
 
 	/* Make sure the host task fpsimd state is visible to hyp: */
-	ret = kvm_share_hyp(fpsimd, fpsimd + 1);
+	ret = kvm_share_hyp(uw, uw + 1);
 	if (ret)
 		return ret;
 
-	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
+	vcpu->arch.host_uw = kern_hyp_va(uw);
 
 	/*
 	 * We need to keep current's task_struct pinned until its data has been
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index a038320cdb08..27fcdfd432b9 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -371,7 +371,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
 
 	/* Write out the host state if it's in the registers */
 	if (vcpu->arch.fp_state == FP_STATE_HOST_OWNED)
-		__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
+		__fpsimd_save_state(&(vcpu->arch.host_uw->fpsimd_state));
 
 	/* Restore the guest state */
 	if (sve_guest)
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 2385fd03ed87..eb2208009875 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -42,7 +42,7 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 	hyp_vcpu->vcpu.arch.fp_state	= host_vcpu->arch.fp_state;
 
 	hyp_vcpu->vcpu.arch.debug_ptr	= kern_hyp_va(host_vcpu->arch.debug_ptr);
-	hyp_vcpu->vcpu.arch.host_fpsimd_state = host_vcpu->arch.host_fpsimd_state;
+	hyp_vcpu->vcpu.arch.host_uw	= host_vcpu->arch.host_uw;
 
 	hyp_vcpu->vcpu.arch.vsesr_el2	= host_vcpu->arch.vsesr_el2;
 
@@ -64,7 +64,7 @@ static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 	host_vcpu->arch.fault		= hyp_vcpu->vcpu.arch.fault;
 
 	host_vcpu->arch.iflags		= hyp_vcpu->vcpu.arch.iflags;
-	host_vcpu->arch.fp_state	= hyp_vcpu->vcpu.arch.fp_state;
+	host_vcpu->arch.host_uw		= hyp_vcpu->vcpu.arch.host_uw;
 
 	host_cpu_if->vgic_hcr		= hyp_cpu_if->vgic_hcr;
 	for (i = 0; i < hyp_cpu_if->used_lrs; ++i)

-- 
2.30.2