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From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Tianyu Lan <ltykernel@gmail.com>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
	sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com,
	luto@kernel.org, peterz@infradead.org,
	boris.ostrovsky@oracle.com, jgross@suse.com,
	sstabellini@kernel.org, joro@8bytes.org, will@kernel.org,
	davem@davemloft.net, kuba@kernel.org, jejb@linux.ibm.com,
	martin.petersen@oracle.com, arnd@arndb.de, hch@lst.de,
	m.szyprowski@samsung.com, robin.murphy@arm.com,
	thomas.lendacky@amd.com, brijesh.singh@amd.com, ardb@kernel.org,
	Tianyu.Lan@microsoft.com, rientjes@google.com,
	martin.b.radev@gmail.com, akpm@linux-foundation.org,
	rppt@kernel.org, kirill.shutemov@linux.intel.com,
	aneesh.kumar@linux.ibm.com, krish.sadhukhan@oracle.com,
	saravanand@fb.com, xen-devel@lists.xenproject.org,
	pgonda@google.com, david@redhat.com, keescook@chromium.org,
	hannes@cmpxchg.org, sfr@canb.auug.org.au,
	michael.h.kelley@microsoft.com, iommu@lists.linux-foundation.org,
	linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	netdev@vger.kernel.org, vkuznets@redhat.com,
	anparri@microsoft.com
Subject: Re: [PATCH 10/13] x86/Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM
Date: Thu, 29 Jul 2021 12:29:21 -0400	[thread overview]
Message-ID: <YQLXYVaWWdBfF7Sm@fedora> (raw)
In-Reply-To: <20210728145232.285861-11-ltykernel@gmail.com>

On Wed, Jul 28, 2021 at 10:52:25AM -0400, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> In Isolation VM with AMD SEV, bounce buffer needs to be accessed via
> extra address space which is above shared_gpa_boundary
> (E.G 39 bit address line) reported by Hyper-V CPUID ISOLATION_CONFIG.
> The access physical address will be original physical address +
> shared_gpa_boundary. The shared_gpa_boundary in the AMD SEV SNP
> spec is called virtual top of memory(vTOM). Memory addresses below
> vTOM are automatically treated as private while memory above
> vTOM is treated as shared.
> 
> Use dma_map_decrypted() in the swiotlb code, store remap address returned
> and use the remap address to copy data from/to swiotlb bounce buffer.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> ---
>  include/linux/swiotlb.h |  4 ++++
>  kernel/dma/swiotlb.c    | 11 ++++++++---
>  2 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index f507e3eacbea..584560ecaa8e 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -72,6 +72,9 @@ extern enum swiotlb_force swiotlb_force;
>   * @end:	The end address of the swiotlb memory pool. Used to do a quick
>   *		range check to see if the memory was in fact allocated by this
>   *		API.
> + * @vaddr:	The vaddr of the swiotlb memory pool. The swiotlb
> + *		memory pool may be remapped in the memory encrypted case and store
> + *		virtual address for bounce buffer operation.
>   * @nslabs:	The number of IO TLB blocks (in groups of 64) between @start and
>   *		@end. For default swiotlb, this is command line adjustable via
>   *		setup_io_tlb_npages.
> @@ -89,6 +92,7 @@ extern enum swiotlb_force swiotlb_force;
>  struct io_tlb_mem {
>  	phys_addr_t start;
>  	phys_addr_t end;
> +	void *vaddr;
>  	unsigned long nslabs;
>  	unsigned long used;
>  	unsigned int index;
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 1fa81c096c1d..6866e5784b53 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -194,8 +194,13 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
>  		mem->slots[i].alloc_size = 0;
>  	}
>  
> -	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
> -	memset(vaddr, 0, bytes);
> +	mem->vaddr = dma_map_decrypted(vaddr, bytes);
> +	if (!mem->vaddr) {
> +		pr_err("Failed to decrypt memory.\n");

I am wondering if it would be worth returning an error code in this
function instead of just printing an error?

For this patch I think it is Ok, but perhaps going forward this would be
better done as I am thinking - is there some global guest->hyperv
reporting mechanism so that if this fails - it ends up being bubbled up
to the HyperV console-ish?

And ditto for other hypervisors?


> +		return;
> +	}
> +
> +	memset(mem->vaddr, 0, bytes);
>  }
>  
>  int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
> @@ -360,7 +365,7 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
>  	phys_addr_t orig_addr = mem->slots[index].orig_addr;
>  	size_t alloc_size = mem->slots[index].alloc_size;
>  	unsigned long pfn = PFN_DOWN(orig_addr);
> -	unsigned char *vaddr = phys_to_virt(tlb_addr);
> +	unsigned char *vaddr = mem->vaddr + tlb_addr - mem->start;
>  	unsigned int tlb_offset;
>  
>  	if (orig_addr == INVALID_PHYS_ADDR)
> -- 
> 2.25.1
> 

  reply	other threads:[~2021-07-29 16:30 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-28 14:52 [PATCH 00/13] x86/Hyper-V: Add Hyper-V Isolation VM support Tianyu Lan
2021-07-28 14:52 ` [PATCH 01/13] x86/HV: Initialize GHCB page in Isolation VM Tianyu Lan
2021-08-02 11:53   ` Joerg Roedel
2021-08-02 12:35     ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 02/13] x86/HV: Initialize shared memory boundary in the " Tianyu Lan
2021-07-28 14:52 ` [PATCH 03/13] x86/HV: Add new hvcall guest address host visibility support Tianyu Lan
2021-07-28 15:29   ` Dave Hansen
2021-07-29 12:49     ` Tianyu Lan
2021-08-02 12:01     ` Joerg Roedel
2021-08-02 12:59       ` Tianyu Lan
2021-08-02 13:11       ` Juergen Gross
2021-08-02 13:30         ` Joerg Roedel
2021-07-28 17:06   ` Dave Hansen
2021-07-29 13:01     ` Tianyu Lan
2021-07-29 14:09       ` Dave Hansen
2021-07-29 15:02         ` Tianyu Lan
2021-07-29 16:05           ` Dave Hansen
2021-07-30  2:52             ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 04/13] HV: Mark vmbus ring buffer visible to host in Isolation VM Tianyu Lan
2021-08-02 12:07   ` Joerg Roedel
2021-08-02 12:56     ` Tianyu Lan
2021-08-02 12:59       ` Joerg Roedel
2021-08-02 13:08         ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 05/13] HV: Add Write/Read MSR registers via ghcb page Tianyu Lan
2021-08-02 12:28   ` Joerg Roedel
2021-08-02 13:18     ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 06/13] HV: Add ghcb hvcall support for SNP VM Tianyu Lan
2021-08-02 12:39   ` Joerg Roedel
2021-08-02 13:32     ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 07/13] HV/Vmbus: Add SNP support for VMbus channel initiate message Tianyu Lan
2021-08-02 12:58   ` Joerg Roedel
2021-07-28 14:52 ` [PATCH 08/13] HV/Vmbus: Initialize VMbus ring buffer for Isolation VM Tianyu Lan
2021-07-28 14:52 ` [PATCH 09/13] DMA: Add dma_map_decrypted/dma_unmap_encrypted() function Tianyu Lan
2021-07-29 15:13   ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 10/13] x86/Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM Tianyu Lan
2021-07-29 16:29   ` Konrad Rzeszutek Wilk [this message]
2021-07-30  4:10     ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 11/13] HV/IOMMU: Enable swiotlb bounce buffer for Isolation VM Tianyu Lan
2021-07-28 14:52 ` [PATCH 12/13] HV/Netvsc: Add Isolation VM support for netvsc driver Tianyu Lan
2021-07-28 14:52 ` [PATCH 13/13] HV/Storvsc: Add Isolation VM support for storvsc driver Tianyu Lan
2021-08-02 13:20   ` Joerg Roedel
2021-08-02 14:08     ` Tianyu Lan

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