Commit 122733f3 authored Mar 01, 2024 by Marc Zyngier Committed by Junhao He Nov 22, 2024

KVM: arm64: Exclude host_fpsimd_state pointer from kvm_vcpu_arch

mainline inclusion
from mainline-v6.9-rc1
commit 51e09b5572d665645ce394f94f24a7d6ec32bda9
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8EC9K
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=51e09b5572d665645ce394f94f24a7d6ec32bda9



--------------------------------

As the name of the field indicates, host_fpsimd_state is strictly
a host piece of data, and we reset this pointer on each PID change.

So let's move it where it belongs, and set it at load-time. Although
this is slightly more often, it is a well defined life-cycle which
matches other pieces of data.

Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Junhao He <hejunhao3@huawei.com>

parent c91def97

arch/arm64/include/asm/kvm_host.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -463,6 +463,7 @@ struct kvm_cpu_context {
		*/
		struct kvm_host_data {
		struct kvm_cpu_context host_ctxt;
		struct user_fpsimd_state fpsimd_state; / hyp VA */

		/*
		* host_debug_state contains the host registers which are
		@@ -580,7 +581,6 @@ 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 task_struct *parent_task;

		/* VGIC state */

arch/arm64/kvm/fpsimd.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -49,8 +49,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
		if (ret)
		return ret;

		vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);

		/*
		* We need to keep current's task_struct pinned until its data has been
		* unshared with the hypervisor to make sure it is not re-used by the
		@@ -87,6 +85,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
		* FP_STATE_FREE if the flag set.
		*/
		vcpu->arch.fp_state = FP_STATE_HOST_OWNED;
		*host_data_ptr(fpsimd_state) = kern_hyp_va(&current->thread.uw.fpsimd_state);

		vcpu_clear_flag(vcpu, HOST_SVE_ENABLED);
		if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)

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

+1 −1

Original line number	Diff line number	Diff line
		@@ -365,7 +365,7 @@ 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(*host_data_ptr(fpsimd_state));

		/* Restore the guest state */
		if (sve_guest)

arch/arm64/kvm/hyp/nvhe/hyp-main.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -42,7 +42,6 @@ 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.vsesr_el2 = host_vcpu->arch.vsesr_el2;