linux-kernel - Re: [PATCH v2 13/30] s390/pci: return status from zpci_refresh

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Message-ID: <2fad3da6-987a-ae62-9da2-f9184b0c91cb@linux.ibm.com>
Date:   Wed, 19 Jan 2022 19:13:55 +0100
From:   Pierre Morel <pmorel@...ux.ibm.com>
To:     Matthew Rosato <mjrosato@...ux.ibm.com>, linux-s390@...r.kernel.org
Cc:     alex.williamson@...hat.com, cohuck@...hat.com,
        schnelle@...ux.ibm.com, farman@...ux.ibm.com,
        borntraeger@...ux.ibm.com, hca@...ux.ibm.com, gor@...ux.ibm.com,
        gerald.schaefer@...ux.ibm.com, agordeev@...ux.ibm.com,
        frankja@...ux.ibm.com, david@...hat.com, imbrenda@...ux.ibm.com,
        vneethv@...ux.ibm.com, oberpar@...ux.ibm.com, freude@...ux.ibm.com,
        thuth@...hat.com, pasic@...ux.ibm.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 13/30] s390/pci: return status from zpci_refresh_trans



On 1/14/22 21:31, Matthew Rosato wrote:
> Current callers of zpci_refresh_trans don't need to interrogate the status
> returned from the underlying instructions.  However, a subsequent patch
> will add a KVM caller that needs this information.  Add a new argument to
> zpci_refresh_trans to pass the address of a status byte and update
> existing call sites to provide it.
> 
> Signed-off-by: Matthew Rosato <mjrosato@...ux.ibm.com>

Reviewed-by: Pierre Morel <pmorel@...ux.ibm.com>


> ---
>   arch/s390/include/asm/pci_insn.h |  2 +-
>   arch/s390/pci/pci_dma.c          |  6 ++++--
>   arch/s390/pci/pci_insn.c         | 10 +++++-----
>   drivers/iommu/s390-iommu.c       |  4 +++-
>   4 files changed, 13 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/s390/include/asm/pci_insn.h b/arch/s390/include/asm/pci_insn.h
> index 5331082fa516..32759c407b8f 100644
> --- a/arch/s390/include/asm/pci_insn.h
> +++ b/arch/s390/include/asm/pci_insn.h
> @@ -135,7 +135,7 @@ union zpci_sic_iib {
>   DECLARE_STATIC_KEY_FALSE(have_mio);
>   
>   u8 zpci_mod_fc(u64 req, struct zpci_fib *fib, u8 *status);
> -int zpci_refresh_trans(u64 fn, u64 addr, u64 range);
> +int zpci_refresh_trans(u64 fn, u64 addr, u64 range, u8 *status);
>   int __zpci_load(u64 *data, u64 req, u64 offset);
>   int zpci_load(u64 *data, const volatile void __iomem *addr, unsigned long len);
>   int __zpci_store(u64 data, u64 req, u64 offset);
> diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
> index a81de48d5ea7..b0a2380bcad8 100644
> --- a/arch/s390/pci/pci_dma.c
> +++ b/arch/s390/pci/pci_dma.c
> @@ -23,8 +23,9 @@ static u32 s390_iommu_aperture_factor = 1;
>   
>   static int zpci_refresh_global(struct zpci_dev *zdev)
>   {
> +	u8 status;
>   	return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
> -				  zdev->iommu_pages * PAGE_SIZE);
> +				  zdev->iommu_pages * PAGE_SIZE, &status);
>   }
>   
>   unsigned long *dma_alloc_cpu_table(void)
> @@ -183,6 +184,7 @@ static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
>   			   size_t size, int flags)
>   {
>   	unsigned long irqflags;
> +	u8 status;
>   	int ret;
>   
>   	/*
> @@ -201,7 +203,7 @@ static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
>   	}
>   
>   	ret = zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
> -				 PAGE_ALIGN(size));
> +				 PAGE_ALIGN(size), &status);
>   	if (ret == -ENOMEM && !s390_iommu_strict) {
>   		/* enable the hypervisor to free some resources */
>   		if (zpci_refresh_global(zdev))
> diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
> index 0509554301c7..ca6399d52767 100644
> --- a/arch/s390/pci/pci_insn.c
> +++ b/arch/s390/pci/pci_insn.c
> @@ -77,20 +77,20 @@ static inline u8 __rpcit(u64 fn, u64 addr, u64 range, u8 *status)
>   	return cc;
>   }
>   
> -int zpci_refresh_trans(u64 fn, u64 addr, u64 range)
> +int zpci_refresh_trans(u64 fn, u64 addr, u64 range, u8 *status)
>   {
> -	u8 cc, status;
> +	u8 cc;
>   
>   	do {
> -		cc = __rpcit(fn, addr, range, &status);
> +		cc = __rpcit(fn, addr, range, status);
>   		if (cc == 2)
>   			udelay(ZPCI_INSN_BUSY_DELAY);
>   	} while (cc == 2);
>   
>   	if (cc)
> -		zpci_err_insn(cc, status, addr, range);
> +		zpci_err_insn(cc, *status, addr, range);
>   
> -	if (cc == 1 && (status == 4 || status == 16))
> +	if (cc == 1 && (*status == 4 || *status == 16))
>   		return -ENOMEM;
>   
>   	return (cc) ? -EIO : 0;
> diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
> index 50860ebdd087..845bb99c183e 100644
> --- a/drivers/iommu/s390-iommu.c
> +++ b/drivers/iommu/s390-iommu.c
> @@ -214,6 +214,7 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
>   	unsigned long irq_flags, nr_pages, i;
>   	unsigned long *entry;
>   	int rc = 0;
> +	u8 status;
>   
>   	if (dma_addr < s390_domain->domain.geometry.aperture_start ||
>   	    dma_addr + size > s390_domain->domain.geometry.aperture_end)
> @@ -238,7 +239,8 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
>   	spin_lock(&s390_domain->list_lock);
>   	list_for_each_entry(domain_device, &s390_domain->devices, list) {
>   		rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
> -					start_dma_addr, nr_pages * PAGE_SIZE);
> +					start_dma_addr, nr_pages * PAGE_SIZE,
> +					&status);
>   		if (rc)
>   			break;
>   	}
> 

-- 
Pierre Morel
IBM Lab Boeblingen