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 f15a014..7aeef57 100644
--- 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 @@
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 @@
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 @@
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 @@
/* 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 @@
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 @@
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 @@
.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,
