Commit 53227810 authored by Claudio Imbrenda's avatar Claudio Imbrenda Committed by Christian Borntraeger
Browse files

KVM: s390/mm: handle guest unpin events 



The current code tries to first pin shared pages, if that fails (e.g.
because the page is not shared) it will export them. For shared pages
this means that we get a new intercept telling us that the guest is
unsharing that page. We will unpin the page at that point in time,
following the same rules as for making a page secure (i.e. waiting for
writeback, no elevated page references, etc.)

Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>

Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent d274995e

arch/s390/kvm/intercept.c

+29 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <asm/asm-offsets.h>

#include <asm/irq.h>

#include <asm/sysinfo.h>

#include <asm/uv.h>



#include "kvm-s390.h"

#include "gaccess.h"
@@ -484,12 +485,40 @@ static int handle_pv_sclp(struct kvm_vcpu *vcpu) 
	return 0;

}



static int handle_pv_uvc(struct kvm_vcpu *vcpu)

{

	struct uv_cb_share *guest_uvcb = (void *)vcpu->arch.sie_block->sidad;

	struct uv_cb_cts uvcb = {

		.header.cmd	= UVC_CMD_UNPIN_PAGE_SHARED,

		.header.len	= sizeof(uvcb),

		.guest_handle	= kvm_s390_pv_get_handle(vcpu->kvm),

		.gaddr		= guest_uvcb->paddr,

	};

	int rc;



	if (guest_uvcb->header.cmd != UVC_CMD_REMOVE_SHARED_ACCESS) {

		WARN_ONCE(1, "Unexpected notification intercept for UVC 0x%x\n",

			  guest_uvcb->header.cmd);

		return 0;

	}

	rc = gmap_make_secure(vcpu->arch.gmap, uvcb.gaddr, &uvcb);

	/*

	 * If the unpin did not succeed, the guest will exit again for the UVC

	 * and we will retry the unpin.

	 */

	if (rc == -EINVAL)

		return 0;

	return rc;

}



static int handle_pv_notification(struct kvm_vcpu *vcpu)

{

	if (vcpu->arch.sie_block->ipa == 0xb210)

		return handle_pv_spx(vcpu);

	if (vcpu->arch.sie_block->ipa == 0xb220)

		return handle_pv_sclp(vcpu);

	if (vcpu->arch.sie_block->ipa == 0xb9a4)

		return handle_pv_uvc(vcpu);



	return handle_instruction(vcpu);

}

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