Commit e0ead41a authored by Dominik Dingel's avatar Dominik Dingel Committed by Christian Borntraeger
Browse files

KVM: async_pf: Provide additional direct page notification 



By setting a Kconfig option, the architecture can control when
guest notifications will be presented by the apf backend.
There is the default batch mechanism, working as before, where the vcpu
thread should pull in this information.
Opposite to this, there is now the direct mechanism, that will push the
information to the guest.
This way s390 can use an already existing architecture interface.

Still the vcpu thread should call check_completion to cleanup leftovers.

Signed-off-by: default avatarDominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 24eb3a82

arch/x86/kvm/mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -3328,7 +3328,7 @@ static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn) 
	arch.direct_map = vcpu->arch.mmu.direct_map;

	arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu);



	return kvm_setup_async_pf(vcpu, gva, gfn, &arch);

	return kvm_setup_async_pf(vcpu, gva, gfn_to_hva(vcpu->kvm, gfn), &arch);

}



static bool can_do_async_pf(struct kvm_vcpu *vcpu)

include/linux/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -192,7 +192,7 @@ struct kvm_async_pf { 


void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu);

void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu);

int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,

int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,

		       struct kvm_arch_async_pf *arch);

int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu);

#endif

virt/kvm/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -22,6 +22,10 @@ config KVM_MMIO 
config KVM_ASYNC_PF

       bool



# Toggle to switch between direct notification and batch job

config KVM_ASYNC_PF_SYNC

       bool



config HAVE_KVM_MSI

       bool

virt/kvm/async_pf.c

+18 −2
Original line number Diff line number Diff line
@@ -28,6 +28,21 @@ 
#include "async_pf.h"

#include <trace/events/kvm.h>



static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu,

					       struct kvm_async_pf *work)

{

#ifdef CONFIG_KVM_ASYNC_PF_SYNC

	kvm_arch_async_page_present(vcpu, work);

#endif

}

static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu,

						struct kvm_async_pf *work)

{

#ifndef CONFIG_KVM_ASYNC_PF_SYNC

	kvm_arch_async_page_present(vcpu, work);

#endif

}



static struct kmem_cache *async_pf_cache;



int kvm_async_pf_init(void)
@@ -69,6 +84,7 @@ static void async_pf_execute(struct work_struct *work) 
	down_read(&mm->mmap_sem);

	get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);

	up_read(&mm->mmap_sem);

	kvm_async_page_present_sync(vcpu, apf);

	unuse_mm(mm);



	spin_lock(&vcpu->async_pf.lock);
@@ -138,7 +154,7 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) 
	}

}



int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,

int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,

		       struct kvm_arch_async_pf *arch)

{

	struct kvm_async_pf *work;
@@ -159,7 +175,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, 
	work->wakeup_all = false;

	work->vcpu = vcpu;

	work->gva = gva;

	work->addr = gfn_to_hva(vcpu->kvm, gfn);

	work->addr = hva;

	work->arch = *arch;

	work->mm = current->mm;

	atomic_inc(&work->mm->mm_count);

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