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Commit 8221c137 authored by Suravee Suthikulpanit's avatar Suravee Suthikulpanit Committed by Paolo Bonzini
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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: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: default avatarRadim 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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3bbf3565

arch/x86/kvm/svm.c

+89 −0
Original line number Diff line number Diff line
@@ -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 @@ static int avic_vm_init(struct kvm *kvm) 
	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,