[PART1,RFC,9/9] svm: Manage vcpu load/unload when enable AVIC

Commit Message

Suthikulpanit, Suravee Feb. 12, 2016, 1:59 p.m. UTC

When a vcpu is loaded/unloaded to a physical core, we need to update
information in the Physical APIC-ID table accordingly.

Signed-off-by: Suravee Suthikulpanit <[e-mail]>
---
 arch/x86/kvm/svm.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

Comments

Paolo Bonzini Feb. 12, 2016, 3:46 p.m. UTC | #1

On 12/02/2016 14:59, Suravee Suthikulpanit wrote:
> +
> +	if (is_running) {
> +		phys_addr_t pa = PFN_PHYS(page_to_pfn(svm->avic_bk_page));
> +
> +		entry->bk_pg_ptr = (pa >> 12) & 0xffffffffff;
> +		entry->valid = 1;
> +		entry->host_phy_apic_id = h_phy_apic_id;
> +		barrier();
> +		entry->is_running = is_running;

I'm not sure if you can rely on the compiler doing the right thing here.
 I would prefer something like:

	new_entry = READ_ONCE(entry);
	new_entry.bk_pg_ptr = (pa >> 12) & 0xffffffffff;
	new_entry.valid = 1;
	new_entry.host_phy_apic_id = h_phy_apic_id;
	new_entry.is_running = is_running;
	WRITE_ONCE(entry, new_entry);

Paolo
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Patch

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 32da657..41e68d2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -32,6 +32,7 @@ 
 #include <linux/trace_events.h>
 #include <linux/slab.h>
 
+#include <asm/apic.h>
 #include <asm/perf_event.h>
 #include <asm/tlbflush.h>
 #include <asm/desc.h>
@@ -1508,6 +1509,61 @@  static int avic_vcpu_init(struct kvm *kvm, struct vcpu_svm *svm, int id)
 	return 0;
 }
 
+static inline int avic_update_iommu(struct kvm_vcpu *vcpu, int cpu,
+				    phys_addr_t pa, bool is_running)
+{
+	if (!kvm_arch_has_assigned_device(vcpu->kvm))
+		return 0;
+
+	/* TODO: We will hook up with IOMMU API at later time */
+	return 0;
+}
+
+static int avic_set_running(struct kvm_vcpu *vcpu, int cpu, bool is_running)
+{
+	int g_phy_apic_id, h_phy_apic_id;
+	struct svm_avic_phy_ait_entry *entry;
+	struct vcpu_svm *svm = to_svm(vcpu);
+	int ret;
+
+	if (!avic)
+		return 0;
+
+	if (!svm)
+		return -EINVAL;
+
+	/* Note: APIC ID = 0xff is used for broadcast.
+	 *       APIC ID > 0xff is reserved.
+	 */
+	g_phy_apic_id = vcpu->vcpu_id;
+	h_phy_apic_id = __default_cpu_present_to_apicid(cpu);
+
+	if ((g_phy_apic_id >= AVIC_PHY_APIC_ID_MAX) ||
+	    (h_phy_apic_id >= AVIC_PHY_APIC_ID_MAX))
+		return -EINVAL;
+
+	entry = avic_get_phy_ait_entry(vcpu, g_phy_apic_id);
+	if (!entry)
+		return -EINVAL;
+
+	if (is_running) {
+		phys_addr_t pa = PFN_PHYS(page_to_pfn(svm->avic_bk_page));
+
+		entry->bk_pg_ptr = (pa >> 12) & 0xffffffffff;
+		entry->valid = 1;
+		entry->host_phy_apic_id = h_phy_apic_id;
+		barrier();
+		entry->is_running = is_running;
+		ret = avic_update_iommu(vcpu, h_phy_apic_id, pa, is_running);
+	} else {
+		ret = avic_update_iommu(vcpu, 0, 0, is_running);
+		barrier();
+		entry->is_running = is_running;
+	}
+
+	return ret;
+}
+
 static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -1628,6 +1684,8 @@  static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		mark_all_dirty(svm->vmcb);
 	}
 
+	avic_set_running(vcpu, cpu, true);
+
 #ifdef CONFIG_X86_64
 	rdmsrl(MSR_GS_BASE, to_svm(vcpu)->host.gs_base);
 #endif
@@ -1668,6 +1726,9 @@  static void svm_vcpu_put(struct kvm_vcpu *vcpu)
 #endif
 	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
 		wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
+
+	avic_set_running(vcpu, 0, false);
+
 }
 
 static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)