Re: [PATCH 07/10] KVM: arm64: Save guest's ZCR_EL1 before saving the FPSIMD state
From: Will Deacon <will@kernel.org>
Date: 2021-03-17 17:19:16
Also in:
kvm, kvmarm
On Tue, Mar 16, 2021 at 10:13:09AM +0000, Marc Zyngier wrote:
quoted hunk ↗ jump to hunk
Make sure the guest's ZCR_EL1 is saved before we save/flush the state. This will be useful in later patches. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/fpsimd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 84afca5ed6f2..b5f95abd23f5 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c@@ -121,10 +121,10 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) local_irq_save(flags); if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) { - fpsimd_save_and_flush_cpu_state(); - if (guest_has_sve) __vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR); + + fpsimd_save_and_flush_cpu_state();
I _think_ fpsimd_save_and_flush_cpu_state() contains a RDVL instruction to get at the vector length for sve_get_vl(), and this ends up reading from ZCR_EL1. So I'm not sure it's save to move it like this. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel