svm: Manage vcpu load/unload when enable AVIC

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

Also, when vCPU is blocking/un-blocking (due to halt instruction),
we need to make sure that the is-running bit in set accordingly in the
physical APIC-ID table.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
[Return void from new functions, add WARN_ON when they returned negative
 errno; split load and put into separate function as they have almost
 nothing in common. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f15a01413080c4ddb3d106ac8431d3469042f978..7aeef57a093a76558bea54d06c4189eb7a3cf1c9 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -35,6 +35,7 @@
 #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>
@@ -183,6 +184,7 @@ struct vcpu_svm {
        u32 ldr_reg;
        struct page *avic_backing_page;
        u64 *avic_physical_id_cache;
+       bool avic_is_running;
 };
 
 #define AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK   (0xFF)
@@ -1316,6 +1318,72 @@ free_avic:
        return err;
 }
 
+/**
+ * This function is called during VCPU halt/unhalt.
+ */
+static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
+{
+       u64 entry;
+       int h_physical_id = __default_cpu_present_to_apicid(vcpu->cpu);
+       struct vcpu_svm *svm = to_svm(vcpu);
+
+       if (!kvm_vcpu_apicv_active(vcpu))
+               return;
+
+       svm->avic_is_running = is_run;
+
+       /* ID = 0xff (broadcast), ID > 0xff (reserved) */
+       if (WARN_ON(h_physical_id >= AVIC_MAX_PHYSICAL_ID_COUNT))
+               return;
+
+       entry = READ_ONCE(*(svm->avic_physical_id_cache));
+       WARN_ON(is_run == !!(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK));
+
+       entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+       if (is_run)
+               entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+       WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+}
+
+static void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+{
+       u64 entry;
+       /* ID = 0xff (broadcast), ID > 0xff (reserved) */
+       int h_physical_id = __default_cpu_present_to_apicid(cpu);
+       struct vcpu_svm *svm = to_svm(vcpu);
+
+       if (!kvm_vcpu_apicv_active(vcpu))
+               return;
+
+       if (WARN_ON(h_physical_id >= AVIC_MAX_PHYSICAL_ID_COUNT))
+               return;
+
+       entry = READ_ONCE(*(svm->avic_physical_id_cache));
+       WARN_ON(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK);
+
+       entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK;
+       entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK);
+
+       entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+       if (svm->avic_is_running)
+               entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+
+       WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+}
+
+static void avic_vcpu_put(struct kvm_vcpu *vcpu)
+{
+       u64 entry;
+       struct vcpu_svm *svm = to_svm(vcpu);
+
+       if (!kvm_vcpu_apicv_active(vcpu))
+               return;
+
+       entry = READ_ONCE(*(svm->avic_physical_id_cache));
+       entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+       WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+}
+
 static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 {
        struct vcpu_svm *svm = to_svm(vcpu);
@@ -1379,6 +1447,11 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
                        goto free_page4;
        }
 
+       /* We initialize this flag to true to make sure that the is_running
+        * bit would be set the first time the vcpu is loaded.
+        */
+       svm->avic_is_running = true;
+
        svm->nested.hsave = page_address(hsave_page);
 
        svm->msrpm = page_address(msrpm_pages);
@@ -1455,6 +1528,8 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
        /* This assumes that the kernel never uses MSR_TSC_AUX */
        if (static_cpu_has(X86_FEATURE_RDTSCP))
                wrmsrl(MSR_TSC_AUX, svm->tsc_aux);
+
+       avic_vcpu_load(vcpu, cpu);
 }
 
 static void svm_vcpu_put(struct kvm_vcpu *vcpu)
@@ -1462,6 +1537,8 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
        struct vcpu_svm *svm = to_svm(vcpu);
        int i;
 
+       avic_vcpu_put(vcpu);
+
        ++vcpu->stat.host_state_reload;
        kvm_load_ldt(svm->host.ldt);
 #ifdef CONFIG_X86_64
@@ -1477,6 +1554,16 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
                wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
 }
 
+static void svm_vcpu_blocking(struct kvm_vcpu *vcpu)
+{
+       avic_set_running(vcpu, false);
+}
+
+static void svm_vcpu_unblocking(struct kvm_vcpu *vcpu)
+{
+       avic_set_running(vcpu, true);
+}
+
 static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)
 {
        return to_svm(vcpu)->vmcb->save.rflags;
@@ -4884,6 +4971,8 @@ static struct kvm_x86_ops svm_x86_ops = {
        .prepare_guest_switch = svm_prepare_guest_switch,
        .vcpu_load = svm_vcpu_load,
        .vcpu_put = svm_vcpu_put,
+       .vcpu_blocking = svm_vcpu_blocking,
+       .vcpu_unblocking = svm_vcpu_unblocking,
 
        .update_bp_intercept = update_bp_intercept,
        .get_msr = svm_get_msr,