Re: [Intel-gfx] [PATCH v3 06/10] vfio/ap: Change saved_pfn to saved_iova

[Anthony Krowiak <akrowiak@linux.ibm.com>]

Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>

On 7/8/22 6:44 PM, Nicolin Chen wrote:
> The vfio_ap_ops code maintains both nib address and its PFN, which
> is redundant, merely because vfio_pin/unpin_pages API wanted pfn.
> Since vfio_pin/unpin_pages() now accept "iova", change "saved_pfn"
> to "saved_iova" and remove pfn in the vfio_ap_validate_nib().
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Tested-by: Eric Farman <farman@linux.ibm.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>   drivers/s390/crypto/vfio_ap_ops.c     | 42 +++++++++++----------------
>   drivers/s390/crypto/vfio_ap_private.h |  4 +--
>   2 files changed, 19 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 8a2018ab3cf0..e8856a7e151c 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -112,7 +112,7 @@ static void vfio_ap_wait_for_irqclear(int apqn)
>    *
>    * Unregisters the ISC in the GIB when the saved ISC not invalid.
>    * Unpins the guest's page holding the NIB when it exists.
> - * Resets the saved_pfn and saved_isc to invalid values.
> + * Resets the saved_iova and saved_isc to invalid values.
>    */
>   static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q)
>   {
> @@ -123,9 +123,9 @@ static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q)
>   		kvm_s390_gisc_unregister(q->matrix_mdev->kvm, q->saved_isc);
>   		q->saved_isc = VFIO_AP_ISC_INVALID;
>   	}
> -	if (q->saved_pfn && !WARN_ON(!q->matrix_mdev)) {
> -		vfio_unpin_pages(&q->matrix_mdev->vdev, q->saved_pfn << PAGE_SHIFT, 1);
> -		q->saved_pfn = 0;
> +	if (q->saved_iova && !WARN_ON(!q->matrix_mdev)) {
> +		vfio_unpin_pages(&q->matrix_mdev->vdev, q->saved_iova, 1);
> +		q->saved_iova = 0;
>   	}
>   }
>   
> @@ -189,27 +189,19 @@ static struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)
>    *
>    * @vcpu: the object representing the vcpu executing the PQAP(AQIC) instruction.
>    * @nib: the location for storing the nib address.
> - * @g_pfn: the location for storing the page frame number of the page containing
> - *	   the nib.
>    *
>    * When the PQAP(AQIC) instruction is executed, general register 2 contains the
>    * address of the notification indicator byte (nib) used for IRQ notification.
> - * This function parses the nib from gr2 and calculates the page frame
> - * number for the guest of the page containing the nib. The values are
> - * stored in @nib and @g_pfn respectively.
> - *
> - * The g_pfn of the nib is then validated to ensure the nib address is valid.
> + * This function parses and validates the nib from gr2.
>    *
>    * Return: returns zero if the nib address is a valid; otherwise, returns
>    *	   -EINVAL.
>    */
> -static int vfio_ap_validate_nib(struct kvm_vcpu *vcpu, unsigned long *nib,
> -				unsigned long *g_pfn)
> +static int vfio_ap_validate_nib(struct kvm_vcpu *vcpu, dma_addr_t *nib)
>   {
>   	*nib = vcpu->run->s.regs.gprs[2];
> -	*g_pfn = *nib >> PAGE_SHIFT;
>   
> -	if (kvm_is_error_hva(gfn_to_hva(vcpu->kvm, *g_pfn)))
> +	if (kvm_is_error_hva(gfn_to_hva(vcpu->kvm, *nib >> PAGE_SHIFT)))
>   		return -EINVAL;
>   
>   	return 0;
> @@ -239,34 +231,34 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
>   						 int isc,
>   						 struct kvm_vcpu *vcpu)
>   {
> -	unsigned long nib;
>   	struct ap_qirq_ctrl aqic_gisa = {};
>   	struct ap_queue_status status = {};
>   	struct kvm_s390_gisa *gisa;
>   	int nisc;
>   	struct kvm *kvm;
> -	unsigned long g_pfn, h_pfn;
> +	unsigned long h_pfn;
>   	phys_addr_t h_nib;
> +	dma_addr_t nib;
>   	int ret;
>   
>   	/* Verify that the notification indicator byte address is valid */
> -	if (vfio_ap_validate_nib(vcpu, &nib, &g_pfn)) {
> -		VFIO_AP_DBF_WARN("%s: invalid NIB address: nib=%#lx, g_pfn=%#lx, apqn=%#04x\n",
> -				 __func__, nib, g_pfn, q->apqn);
> +	if (vfio_ap_validate_nib(vcpu, &nib)) {
> +		VFIO_AP_DBF_WARN("%s: invalid NIB address: nib=%pad, apqn=%#04x\n",
> +				 __func__, &nib, q->apqn);
>   
>   		status.response_code = AP_RESPONSE_INVALID_ADDRESS;
>   		return status;
>   	}
>   
> -	ret = vfio_pin_pages(&q->matrix_mdev->vdev, g_pfn << PAGE_SHIFT, 1,
> +	ret = vfio_pin_pages(&q->matrix_mdev->vdev, nib, 1,
>   			     IOMMU_READ | IOMMU_WRITE, &h_pfn);
>   	switch (ret) {
>   	case 1:
>   		break;
>   	default:
>   		VFIO_AP_DBF_WARN("%s: vfio_pin_pages failed: rc=%d,"
> -				 "nib=%#lx, g_pfn=%#lx, apqn=%#04x\n",
> -				 __func__, ret, nib, g_pfn, q->apqn);
> +				 "nib=%pad, apqn=%#04x\n",
> +				 __func__, ret, &nib, q->apqn);
>   
>   		status.response_code = AP_RESPONSE_INVALID_ADDRESS;
>   		return status;
> @@ -296,12 +288,12 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
>   	case AP_RESPONSE_NORMAL:
>   		/* See if we did clear older IRQ configuration */
>   		vfio_ap_free_aqic_resources(q);
> -		q->saved_pfn = g_pfn;
> +		q->saved_iova = nib;
>   		q->saved_isc = isc;
>   		break;
>   	case AP_RESPONSE_OTHERWISE_CHANGED:
>   		/* We could not modify IRQ setings: clear new configuration */
> -		vfio_unpin_pages(&q->matrix_mdev->vdev, g_pfn << PAGE_SHIFT, 1);
> +		vfio_unpin_pages(&q->matrix_mdev->vdev, nib, 1);
>   		kvm_s390_gisc_unregister(kvm, isc);
>   		break;
>   	default:
> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
> index a26efd804d0d..479b205179bd 100644
> --- a/drivers/s390/crypto/vfio_ap_private.h
> +++ b/drivers/s390/crypto/vfio_ap_private.h
> @@ -102,13 +102,13 @@ struct ap_matrix_mdev {
>    * struct vfio_ap_queue - contains the data associated with a queue bound to the
>    *			  vfio_ap device driver
>    * @matrix_mdev: the matrix mediated device
> - * @saved_pfn: the guest PFN pinned for the guest
> + * @saved_iova: the notification indicator byte (nib) address
>    * @apqn: the APQN of the AP queue device
>    * @saved_isc: the guest ISC registered with the GIB interface
>    */
>   struct vfio_ap_queue {
>   	struct ap_matrix_mdev *matrix_mdev;
> -	unsigned long saved_pfn;
> +	dma_addr_t saved_iova;
>   	int	apqn;
>   #define VFIO_AP_ISC_INVALID 0xff
>   	unsigned char saved_isc;