[PATCH v5 7/8] KVM: VMX: Update PID-pointer table entry when APIC ID is changed

[Zeng Guang <guang.zeng@xxxxxxxxx>]

In xAPIC mode, guest is allowed to modify APIC ID at runtime.
If IPI virtualization is enabled, corresponding entry in
PID-pointer table need change accordingly.

Signed-off-by: Zeng Guang <guang.zeng@xxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/lapic.c            |  7 +++++--
 arch/x86/kvm/vmx/vmx.c          | 12 ++++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2164b9f4c7b0..753bf2a7cebc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1493,6 +1493,7 @@ struct kvm_x86_ops {
 	int (*complete_emulated_msr)(struct kvm_vcpu *vcpu, int err);
 
 	void (*vcpu_deliver_sipi_vector)(struct kvm_vcpu *vcpu, u8 vector);
+	void (*update_ipiv_pid_entry)(struct kvm_vcpu *vcpu, u8 old_id, u8 new_id);
 };
 
 struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 3ce7142ba00e..83c2c7594bcd 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2007,9 +2007,12 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
 
 	switch (reg) {
 	case APIC_ID:		/* Local APIC ID */
-		if (!apic_x2apic_mode(apic))
+		if (!apic_x2apic_mode(apic)) {
+			u8 old_id = kvm_lapic_get_reg(apic, APIC_ID) >> 24;
+
 			kvm_apic_set_xapic_id(apic, val >> 24);
-		else
+			kvm_x86_ops.update_ipiv_pid_entry(apic->vcpu, old_id, val >> 24);
+		} else
 			ret = 1;
 		break;
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 2e65464d6dee..f21ce15c5eb8 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7633,6 +7633,17 @@ static void vmx_vm_destroy(struct kvm *kvm)
 		free_pages((unsigned long)kvm_vmx->pid_table, MAX_PID_TABLE_ORDER);
 }
 
+static void vmx_update_ipiv_pid_entry(struct kvm_vcpu *vcpu, u8 old_id, u8 new_id)
+{
+	if (enable_ipiv && kvm_vcpu_apicv_active(vcpu)) {
+		u64 *pid_table = to_kvm_vmx(vcpu->kvm)->pid_table;
+
+		WRITE_ONCE(pid_table[old_id], 0);
+		WRITE_ONCE(pid_table[new_id], __pa(&to_vmx(vcpu)->pi_desc) |
+				PID_TABLE_ENTRY_VALID);
+	}
+}
+
 static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.name = "kvm_intel",
 
@@ -7770,6 +7781,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.complete_emulated_msr = kvm_complete_insn_gp,
 
 	.vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,
+	.update_ipiv_pid_entry = vmx_update_ipiv_pid_entry,
 };
 
 static __init void vmx_setup_user_return_msrs(void)
-- 
2.27.0