[PATCH 2/4] KVM: arm64: Introduce flag shadowing TIF_FOREIGN_FPSTATE
From: Marc Zyngier <maz@kernel.org>
Date: 2021-10-21 15:15:45
Also in:
kvmarm, linux-arm-kernel
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
We currently have to maintain a mapping the thread_info structure at EL2 in order to be able to check the TIF_FOREIGN_FPSTATE flag. In order to eventually get rid of this, start with a vcpu flag that shadows the thread flag on each entry into the hypervisor. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/fpsimd.c | 8 ++++++++ arch/arm64/kvm/hyp/include/hyp/switch.h | 2 +- 4 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index f856ab63f092..5a05ff062458 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h@@ -442,6 +442,7 @@ struct kvm_vcpu_arch { #define KVM_ARM64_DEBUG_STATE_SAVE_SPE (1 << 12) /* Save SPE context if active */ #define KVM_ARM64_DEBUG_STATE_SAVE_TRBE (1 << 13) /* Save TRBE context if active */ +#define KVM_ARM64_FP_FOREIGN_FPSTATE (1 << 14) #define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \ KVM_GUESTDBG_USE_SW_BP | \
@@ -737,6 +738,7 @@ long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm, /* Guest/host FPSIMD coordination helpers */ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu); +void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 24a1e86d7128..c610971c7e72 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c@@ -850,6 +850,7 @@ 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 5621020b28de..12186c7d8cd8 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c@@ -86,6 +86,14 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) 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
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index c6e98c7e918b..dbd721a450d3 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h@@ -45,7 +45,7 @@ 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);
--
2.30.2