From: Nianyao Tang <tangnianyao@huawei.com>
Date: Tue, 20 Dec 2022 10:50:24 +0000 (+0800)
Subject: KVM: arm64: Synchronize SMEN on vcpu schedule out
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=59d78a2ec0e9cfba5935f3a0d3f14a771461cded;p=linux.git

KVM: arm64: Synchronize SMEN on vcpu schedule out

If we have VHE and need to reenable SME for host in
kvm_arch_vcpu_put_fp, CPACR.SMEN is modified from 0 to 1. Trap
control for reading SVCR is modified from enable to disable.
Synchronization is needed before reading SVCR later in
fpsimd_save, or it may cause sync exception which can not be
handled by host.

Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Nianyao Tang <tangnianyao@huawei.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221220105024.13484-1-dongbo4@huawei.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---

diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index 02dd7e9ebd391..f5799f5713172 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -184,6 +184,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
 			sysreg_clear_set(CPACR_EL1,
 					 CPACR_EL1_SMEN_EL0EN,
 					 CPACR_EL1_SMEN_EL1EN);
+		isb();
 	}
 
 	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) {