Merge: KVM: arm64: Eagerly switch ZCR_EL{1,2}

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6863

JIRA: https://issues.redhat.com/browse/RHEL-87960
Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=67597227
Upstream Status: v6.14
Tested: Passed, no stuck guest in 100 times of reboots

The upstream commit 59419f1 ("KVM: arm64: Eagerly switch ZCR_EL{1,2}")
was incompletely ported by downstream commit 939b186. This leads to
CPTR_EL2 isn't properly saved and restored on vCPU entrance and exit.

This amends the downstream commit so that the upstream commit is ported
completely to avoid CPTR_EL2 lost on vCPU entrance and exit. The detailed
changes can be seen from the conflict resolution section.

Signed-off-by: Gavin Shan <gshan@redhat.com>

Approved-by: Cornelia Huck <cohuck@redhat.com>
Approved-by: Sebastian Ott <sebott@redhat.com>
Approved-by: Mark Langsdorf <mlangsdo@redhat.com>
Approved-by: Donald Dutile <ddutile@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>
Approved-by: Shaoqin Huang <shahuang@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

arch/arm64/include/asm/kvm_emulate.h

@@ -625,14 +625,14 @@ static __always_inline u64 kvm_get_reset_cptr_el2(struct kvm_vcpu *vcpu)
 	} else if (has_hvhe()) {
 		val = CPACR_ELx_FPEN;
 
-		if (!vcpu_has_sve(vcpu) || !guest_owns_fp_regs())
+		if (cpus_have_final_cap(ARM64_SVE))
 			val |= CPACR_ELx_ZEN;
 		if (cpus_have_final_cap(ARM64_SME))
 			val |= CPACR_ELx_SMEN;
 	} else {
 		val = CPTR_NVHE_EL2_RES1;
 
-		if (vcpu_has_sve(vcpu) && guest_owns_fp_regs())
+		if (!cpus_have_final_cap(ARM64_SVE))
 			val |= CPTR_EL2_TZ;
 		if (!cpus_have_final_cap(ARM64_SME))
 			val |= CPTR_EL2_TSM;

arch/arm64/kvm/hyp/nvhe/switch.c

@@ -63,6 +63,11 @@ static void __activate_cptr_traps(struct kvm_vcpu *vcpu)
 		if (!guest_owns_fp_regs())
 			val |= CPTR_EL2_TFP;
 	}
+
+	if (!guest_owns_fp_regs())
+		__activate_traps_fpsimd32(vcpu);
+
+	kvm_write_cptr_el2(val);
 }
 
 static void __activate_traps(struct kvm_vcpu *vcpu)