[PATCH V3 0/5] x86/Hyper-V: Add Hyper-V Isolation VM support(Second part)

[PATCH V3 0/5] x86/Hyper-V: Add Hyper-V Isolation VM support(Second part)

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hyper-V provides two kinds of Isolation VMs. VBS(Virtualization-based
security) and AMD SEV-SNP unenlightened Isolation VMs. This patchset
is to add support for these Isolation VM support in Linux.

The memory of these vms are encrypted and host can't access guest
memory directly. Hyper-V provides new host visibility hvcall and
the guest needs to call new hvcall to mark memory visible to host
before sharing memory with host. For security, all network/storage
stack memory should not be shared with host and so there is bounce
buffer requests.

Vmbus channel ring buffer already plays bounce buffer role because
all data from/to host needs to copy from/to between the ring buffer
and IO stack memory. So mark vmbus channel ring buffer visible.

For SNP isolation VM, guest needs to access the shared memory via
extra address space which is specified by Hyper-V CPUID HYPERV_CPUID_
ISOLATION_CONFIG. The access physical address of the shared memory
should be bounce buffer memory GPA plus with shared_gpa_boundary
reported by CPUID.

This patchset is to enable swiotlb bounce buffer for netvsc/storvsc
in Isolation VM.

This version follows Michael Kelley suggestion in the following link.
https://lkml.org/lkml/2021/11/24/2044

Change since v2:
     * Remove Hyper-V dma ops and dma_alloc/free_noncontiguous. Add
       hv_map/unmap_memory() to map/umap netvsc rx/tx ring into extra
       address space.
     * Leave mem->vaddr in swiotlb code with phys_to_virt(mem->start)
       when fail to remap swiotlb memory.

Change since v1:
     * Add Hyper-V Isolation support check in the cc_platform_has()
       and return true for guest memory encrypt attr.
     * Remove hv isolation check in the sev_setup_arch()

Tianyu Lan (5):
  Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM
  x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()
  hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM
  scsi: storvsc: Add Isolation VM support for storvsc driver
  hv_netvsc: Add Isolation VM support for netvsc driver

 arch/x86/hyperv/ivm.c             |  28 ++++++
 arch/x86/kernel/cc_platform.c     |  15 ++++
 arch/x86/xen/pci-swiotlb-xen.c    |   3 +-
 drivers/hv/hv_common.c            |  11 +++
 drivers/hv/vmbus_drv.c            |   4 +
 drivers/iommu/hyperv-iommu.c      |  56 ++++++++++++
 drivers/net/hyperv/hyperv_net.h   |   5 ++
 drivers/net/hyperv/netvsc.c       | 136 +++++++++++++++++++++++++++++-
 drivers/net/hyperv/netvsc_drv.c   |   1 +
 drivers/net/hyperv/rndis_filter.c |   2 +
 drivers/scsi/storvsc_drv.c        |  37 ++++----
 include/asm-generic/mshyperv.h    |   2 +
 include/linux/hyperv.h            |  14 +++
 include/linux/swiotlb.h           |   6 ++
 kernel/dma/swiotlb.c              |  47 +++++++++--
 15 files changed, 342 insertions(+), 25 deletions(-)

-- 
2.25.1

[PATCH V3 1/5] Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM

[Tianyu Lan]

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.

Expose swiotlb_unencrypted_base for platforms to set unencrypted
memory base offset and platform calls swiotlb_update_mem_attributes()
to remap swiotlb mem to unencrypted address space. memremap() can
not be called in the early stage and so put remapping code into
swiotlb_update_mem_attributes(). Store remap address and use it to copy
data from/to swiotlb bounce buffer.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v2:
	* Leave mem->vaddr with phys_to_virt(mem->start) when fail
	  to remap swiotlb memory.

Change since v1:
	* Rework comment in the swiotlb_init_io_tlb_mem()
	* Make swiotlb_init_io_tlb_mem() back to return void.
---
 include/linux/swiotlb.h |  6 ++++++
 kernel/dma/swiotlb.c    | 47 ++++++++++++++++++++++++++++++++++++-----
 2 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 569272871375..f6c3638255d5 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -73,6 +73,9 @@ 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.
@@ -92,6 +95,7 @@ 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;
@@ -186,4 +190,6 @@ static inline bool is_swiotlb_for_alloc(struct device *dev)
 }
 #endif /* CONFIG_DMA_RESTRICTED_POOL */
 
+extern phys_addr_t swiotlb_unencrypted_base;
+
 #endif /* __LINUX_SWIOTLB_H */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 8e840fbbed7c..adb9d06af5c8 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -50,6 +50,7 @@
 #include <asm/io.h>
 #include <asm/dma.h>
 
+#include <linux/io.h>
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/iommu-helper.h>
@@ -72,6 +73,8 @@ enum swiotlb_force swiotlb_force;
 
 struct io_tlb_mem io_tlb_default_mem;
 
+phys_addr_t swiotlb_unencrypted_base;
+
 /*
  * Max segment that we can provide which (if pages are contingous) will
  * not be bounced (unless SWIOTLB_FORCE is set).
@@ -155,6 +158,27 @@ static inline unsigned long nr_slots(u64 val)
 	return DIV_ROUND_UP(val, IO_TLB_SIZE);
 }
 
+/*
+ * Remap swioltb memory in the unencrypted physical address space
+ * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
+ * Isolation VMs).
+ */
+void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
+{
+	void *vaddr = NULL;
+
+	if (swiotlb_unencrypted_base) {
+		phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
+
+		vaddr = memremap(paddr, bytes, MEMREMAP_WB);
+		if (!vaddr)
+			pr_err("Failed to map the unencrypted memory %llx size %lx.\n",
+			       paddr, bytes);
+	}
+
+	return vaddr;
+}
+
 /*
  * Early SWIOTLB allocation may be too early to allow an architecture to
  * perform the desired operations.  This function allows the architecture to
@@ -172,7 +196,12 @@ void __init swiotlb_update_mem_attributes(void)
 	vaddr = phys_to_virt(mem->start);
 	bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
 	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
-	memset(vaddr, 0, bytes);
+
+	mem->vaddr = swiotlb_mem_remap(mem, bytes);
+	if (!mem->vaddr)
+		mem->vaddr = vaddr;
+
+	memset(mem->vaddr, 0, bytes);
 }
 
 static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
@@ -196,7 +225,18 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
 		mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
 		mem->slots[i].alloc_size = 0;
 	}
+
+	/*
+	 * If swiotlb_unencrypted_base is set, the bounce buffer memory will
+	 * be remapped and cleared in swiotlb_update_mem_attributes.
+	 */
+	if (swiotlb_unencrypted_base)
+		return;
+
+	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
 	memset(vaddr, 0, bytes);
+	mem->vaddr = vaddr;
+	return;
 }
 
 int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
@@ -318,7 +358,6 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	if (!mem->slots)
 		return -ENOMEM;
 
-	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
 	swiotlb_init_io_tlb_mem(mem, virt_to_phys(tlb), nslabs, true);
 
 	swiotlb_print_info();
@@ -371,7 +410,7 @@ 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, orig_addr_offset;
 
 	if (orig_addr == INVALID_PHYS_ADDR)
@@ -806,8 +845,6 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
 			return -ENOMEM;
 		}
 
-		set_memory_decrypted((unsigned long)phys_to_virt(rmem->base),
-				     rmem->size >> PAGE_SHIFT);
 		swiotlb_init_io_tlb_mem(mem, rmem->base, nslabs, false);
 		mem->force_bounce = true;
 		mem->for_alloc = true;
-- 
2.25.1

Re: [PATCH V3 1/5] Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM

[Tom Lendacky]

On 12/1/21 10:02 AM, 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.
> 
> Expose swiotlb_unencrypted_base for platforms to set unencrypted
> memory base offset and platform calls swiotlb_update_mem_attributes()
> to remap swiotlb mem to unencrypted address space. memremap() can
> not be called in the early stage and so put remapping code into
> swiotlb_update_mem_attributes(). Store remap address and use it to copy
> data from/to swiotlb bounce buffer.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>

This patch results in the following stack trace during a bare-metal boot
on my EPYC system with SME active (e.g. mem_encrypt=on):

[    0.123932] BUG: Bad page state in process swapper  pfn:108001
[    0.123942] page:(____ptrval____) refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x108001
[    0.123946] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
[    0.123952] raw: 0017ffffc0000000 ffff88904f2d5e80 ffff88904f2d5e80 0000000000000000
[    0.123954] raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
[    0.123955] page dumped because: nonzero mapcount
[    0.123957] Modules linked in:
[    0.123961] CPU: 0 PID: 0 Comm: swapper Not tainted 5.16.0-rc3-sos-custom #2
[    0.123964] Hardware name: AMD Corporation
[    0.123967] Call Trace:
[    0.123971]  <TASK>
[    0.123975]  dump_stack_lvl+0x48/0x5e
[    0.123985]  bad_page.cold+0x65/0x96
[    0.123990]  __free_pages_ok+0x3a8/0x410
[    0.123996]  memblock_free_all+0x171/0x1dc
[    0.124005]  mem_init+0x1f/0x14b
[    0.124011]  start_kernel+0x3b5/0x6a1
[    0.124016]  secondary_startup_64_no_verify+0xb0/0xbb
[    0.124022]  </TASK>

I see ~40 of these traces, each for different pfns.

Thanks,
Tom

> ---
> Change since v2:
> 	* Leave mem->vaddr with phys_to_virt(mem->start) when fail
> 	  to remap swiotlb memory.
> 
> Change since v1:
> 	* Rework comment in the swiotlb_init_io_tlb_mem()
> 	* Make swiotlb_init_io_tlb_mem() back to return void.
> ---
>   include/linux/swiotlb.h |  6 ++++++
>   kernel/dma/swiotlb.c    | 47 ++++++++++++++++++++++++++++++++++++-----
>   2 files changed, 48 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 569272871375..f6c3638255d5 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -73,6 +73,9 @@ 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.
> @@ -92,6 +95,7 @@ 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;
> @@ -186,4 +190,6 @@ static inline bool is_swiotlb_for_alloc(struct device *dev)
>   }
>   #endif /* CONFIG_DMA_RESTRICTED_POOL */
>   
> +extern phys_addr_t swiotlb_unencrypted_base;
> +
>   #endif /* __LINUX_SWIOTLB_H */
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 8e840fbbed7c..adb9d06af5c8 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -50,6 +50,7 @@
>   #include <asm/io.h>
>   #include <asm/dma.h>
>   
> +#include <linux/io.h>
>   #include <linux/init.h>
>   #include <linux/memblock.h>
>   #include <linux/iommu-helper.h>
> @@ -72,6 +73,8 @@ enum swiotlb_force swiotlb_force;
>   
>   struct io_tlb_mem io_tlb_default_mem;
>   
> +phys_addr_t swiotlb_unencrypted_base;
> +
>   /*
>    * Max segment that we can provide which (if pages are contingous) will
>    * not be bounced (unless SWIOTLB_FORCE is set).
> @@ -155,6 +158,27 @@ static inline unsigned long nr_slots(u64 val)
>   	return DIV_ROUND_UP(val, IO_TLB_SIZE);
>   }
>   
> +/*
> + * Remap swioltb memory in the unencrypted physical address space
> + * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
> + * Isolation VMs).
> + */
> +void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
> +{
> +	void *vaddr = NULL;
> +
> +	if (swiotlb_unencrypted_base) {
> +		phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
> +
> +		vaddr = memremap(paddr, bytes, MEMREMAP_WB);
> +		if (!vaddr)
> +			pr_err("Failed to map the unencrypted memory %llx size %lx.\n",
> +			       paddr, bytes);
> +	}
> +
> +	return vaddr;
> +}
> +
>   /*
>    * Early SWIOTLB allocation may be too early to allow an architecture to
>    * perform the desired operations.  This function allows the architecture to
> @@ -172,7 +196,12 @@ void __init swiotlb_update_mem_attributes(void)
>   	vaddr = phys_to_virt(mem->start);
>   	bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
>   	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
> -	memset(vaddr, 0, bytes);
> +
> +	mem->vaddr = swiotlb_mem_remap(mem, bytes);
> +	if (!mem->vaddr)
> +		mem->vaddr = vaddr;
> +
> +	memset(mem->vaddr, 0, bytes);
>   }
>   
>   static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
> @@ -196,7 +225,18 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
>   		mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
>   		mem->slots[i].alloc_size = 0;
>   	}
> +
> +	/*
> +	 * If swiotlb_unencrypted_base is set, the bounce buffer memory will
> +	 * be remapped and cleared in swiotlb_update_mem_attributes.
> +	 */
> +	if (swiotlb_unencrypted_base)
> +		return;
> +
> +	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
>   	memset(vaddr, 0, bytes);
> +	mem->vaddr = vaddr;
> +	return;
>   }
>   
>   int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
> @@ -318,7 +358,6 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
>   	if (!mem->slots)
>   		return -ENOMEM;
>   
> -	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
>   	swiotlb_init_io_tlb_mem(mem, virt_to_phys(tlb), nslabs, true);
>   
>   	swiotlb_print_info();
> @@ -371,7 +410,7 @@ 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, orig_addr_offset;
>   
>   	if (orig_addr == INVALID_PHYS_ADDR)
> @@ -806,8 +845,6 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
>   			return -ENOMEM;
>   		}
>   
> -		set_memory_decrypted((unsigned long)phys_to_virt(rmem->base),
> -				     rmem->size >> PAGE_SHIFT);
>   		swiotlb_init_io_tlb_mem(mem, rmem->base, nslabs, false);
>   		mem->force_bounce = true;
>   		mem->for_alloc = true;
> 

Re: [PATCH V3 1/5] Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM

[Tianyu Lan]

On 12/2/2021 10:42 PM, Tom Lendacky wrote:
> On 12/1/21 10:02 AM, 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.
>>
>> Expose swiotlb_unencrypted_base for platforms to set unencrypted
>> memory base offset and platform calls swiotlb_update_mem_attributes()
>> to remap swiotlb mem to unencrypted address space. memremap() can
>> not be called in the early stage and so put remapping code into
>> swiotlb_update_mem_attributes(). Store remap address and use it to copy
>> data from/to swiotlb bounce buffer.
>>
>> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> This patch results in the following stack trace during a bare-metal boot
> on my EPYC system with SME active (e.g. mem_encrypt=on):
> 
> [    0.123932] BUG: Bad page state in process swapper  pfn:108001
> [    0.123942] page:(____ptrval____) refcount:0 mapcount:-128 
> mapping:0000000000000000 index:0x0 pfn:0x108001
> [    0.123946] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
> [    0.123952] raw: 0017ffffc0000000 ffff88904f2d5e80 ffff88904f2d5e80 
> 0000000000000000
> [    0.123954] raw: 0000000000000000 0000000000000000 00000000ffffff7f 
> 0000000000000000
> [    0.123955] page dumped because: nonzero mapcount
> [    0.123957] Modules linked in:
> [    0.123961] CPU: 0 PID: 0 Comm: swapper Not tainted 
> 5.16.0-rc3-sos-custom #2
> [    0.123964] Hardware name: AMD Corporation
> [    0.123967] Call Trace:
> [    0.123971]  <TASK>
> [    0.123975]  dump_stack_lvl+0x48/0x5e
> [    0.123985]  bad_page.cold+0x65/0x96
> [    0.123990]  __free_pages_ok+0x3a8/0x410
> [    0.123996]  memblock_free_all+0x171/0x1dc
> [    0.124005]  mem_init+0x1f/0x14b
> [    0.124011]  start_kernel+0x3b5/0x6a1
> [    0.124016]  secondary_startup_64_no_verify+0xb0/0xbb
> [    0.124022]  </TASK>
> 
> I see ~40 of these traces, each for different pfns.
> 
> Thanks,
> Tom

Hi Tom:
       Thanks for your test. Could you help to test the following patch 
and check whether it can fix the issue.


diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 569272871375..f6c3638255d5 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -73,6 +73,9 @@ 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.
@@ -92,6 +95,7 @@ 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;
@@ -186,4 +190,6 @@ static inline bool is_swiotlb_for_alloc(struct 
device *dev)
  }
  #endif /* CONFIG_DMA_RESTRICTED_POOL */

+extern phys_addr_t swiotlb_unencrypted_base;
+
  #endif /* __LINUX_SWIOTLB_H */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 8e840fbbed7c..34e6ade4f73c 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -50,6 +50,7 @@
  #include <asm/io.h>
  #include <asm/dma.h>

+#include <linux/io.h>
  #include <linux/init.h>
  #include <linux/memblock.h>
  #include <linux/iommu-helper.h>
@@ -72,6 +73,8 @@ enum swiotlb_force swiotlb_force;

  struct io_tlb_mem io_tlb_default_mem;

+phys_addr_t swiotlb_unencrypted_base;
+
  /*
   * Max segment that we can provide which (if pages are contingous) will
   * not be bounced (unless SWIOTLB_FORCE is set).
@@ -155,6 +158,27 @@ static inline unsigned long nr_slots(u64 val)
         return DIV_ROUND_UP(val, IO_TLB_SIZE);
  }

+/*
+ * Remap swioltb memory in the unencrypted physical address space
+ * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
+ * Isolation VMs).
+ */
+void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
+{
+       void *vaddr = NULL;
+
+       if (swiotlb_unencrypted_base) {
+               phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
+
+               vaddr = memremap(paddr, bytes, MEMREMAP_WB);
+               if (!vaddr)
+                       pr_err("Failed to map the unencrypted memory 
%llx size %lx.\n",
+                              paddr, bytes);
+       }
+
+       return vaddr;
+}
+
  /*
   * Early SWIOTLB allocation may be too early to allow an architecture to
   * perform the desired operations.  This function allows the 
architecture to
@@ -172,7 +196,12 @@ void __init swiotlb_update_mem_attributes(void)
         vaddr = phys_to_virt(mem->start);
         bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
         set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
-       memset(vaddr, 0, bytes);
+
+       mem->vaddr = swiotlb_mem_remap(mem, bytes);
+       if (!mem->vaddr)
+               mem->vaddr = vaddr;
+
+       memset(mem->vaddr, 0, bytes);
  }

  static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, 
phys_addr_t start,
@@ -196,7 +225,17 @@ static void swiotlb_init_io_tlb_mem(struct 
io_tlb_mem *mem, phys_addr_t start,
                 mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
                 mem->slots[i].alloc_size = 0;
         }
+
+       /*
+        * If swiotlb_unencrypted_base is set, the bounce buffer memory will
+        * be remapped and cleared in swiotlb_update_mem_attributes.
+        */
+       if (swiotlb_unencrypted_base)
+               return;
+
         memset(vaddr, 0, bytes);
+       mem->vaddr = vaddr;
+       return;
  }

  int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int 
verbose)
@@ -371,7 +410,7 @@ 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, orig_addr_offset;

         if (orig_addr == INVALID_PHYS_ADDR)


Thanks.

Re: [PATCH V3 1/5] Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM

[Tom Lendacky]

On 12/3/21 5:20 AM, Tianyu Lan wrote:
> On 12/2/2021 10:42 PM, Tom Lendacky wrote:
>> On 12/1/21 10:02 AM, 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.
>>>
>>> Expose swiotlb_unencrypted_base for platforms to set unencrypted
>>> memory base offset and platform calls swiotlb_update_mem_attributes()
>>> to remap swiotlb mem to unencrypted address space. memremap() can
>>> not be called in the early stage and so put remapping code into
>>> swiotlb_update_mem_attributes(). Store remap address and use it to copy
>>> data from/to swiotlb bounce buffer.
>>>
>>> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
>>
>> This patch results in the following stack trace during a bare-metal boot
>> on my EPYC system with SME active (e.g. mem_encrypt=on):
>>
>> [    0.123932] BUG: Bad page state in process swapper  pfn:108001
>> [    0.123942] page:(____ptrval____) refcount:0 mapcount:-128 
>> mapping:0000000000000000 index:0x0 pfn:0x108001
>> [    0.123946] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
>> [    0.123952] raw: 0017ffffc0000000 ffff88904f2d5e80 ffff88904f2d5e80 
>> 0000000000000000
>> [    0.123954] raw: 0000000000000000 0000000000000000 00000000ffffff7f 
>> 0000000000000000
>> [    0.123955] page dumped because: nonzero mapcount
>> [    0.123957] Modules linked in:
>> [    0.123961] CPU: 0 PID: 0 Comm: swapper Not tainted 
>> 5.16.0-rc3-sos-custom #2
>> [    0.123964] Hardware name: AMD Corporation
>> [    0.123967] Call Trace:
>> [    0.123971]  <TASK>
>> [    0.123975]  dump_stack_lvl+0x48/0x5e
>> [    0.123985]  bad_page.cold+0x65/0x96
>> [    0.123990]  __free_pages_ok+0x3a8/0x410
>> [    0.123996]  memblock_free_all+0x171/0x1dc
>> [    0.124005]  mem_init+0x1f/0x14b
>> [    0.124011]  start_kernel+0x3b5/0x6a1
>> [    0.124016]  secondary_startup_64_no_verify+0xb0/0xbb
>> [    0.124022]  </TASK>
>>
>> I see ~40 of these traces, each for different pfns.
>>
>> Thanks,
>> Tom
> 
> Hi Tom:
>        Thanks for your test. Could you help to test the following patch 
> and check whether it can fix the issue.

The patch is mangled. Is the only difference where set_memory_decrypted() 
is called?

Thanks,
Tom

> 
> 
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 569272871375..f6c3638255d5 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -73,6 +73,9 @@ 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.
> @@ -92,6 +95,7 @@ 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;
> @@ -186,4 +190,6 @@ static inline bool is_swiotlb_for_alloc(struct device 
> *dev)
>   }
>   #endif /* CONFIG_DMA_RESTRICTED_POOL */
> 
> +extern phys_addr_t swiotlb_unencrypted_base;
> +
>   #endif /* __LINUX_SWIOTLB_H */
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 8e840fbbed7c..34e6ade4f73c 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -50,6 +50,7 @@
>   #include <asm/io.h>
>   #include <asm/dma.h>
> 
> +#include <linux/io.h>
>   #include <linux/init.h>
>   #include <linux/memblock.h>
>   #include <linux/iommu-helper.h>
> @@ -72,6 +73,8 @@ enum swiotlb_force swiotlb_force;
> 
>   struct io_tlb_mem io_tlb_default_mem;
> 
> +phys_addr_t swiotlb_unencrypted_base;
> +
>   /*
>    * Max segment that we can provide which (if pages are contingous) will
>    * not be bounced (unless SWIOTLB_FORCE is set).
> @@ -155,6 +158,27 @@ static inline unsigned long nr_slots(u64 val)
>          return DIV_ROUND_UP(val, IO_TLB_SIZE);
>   }
> 
> +/*
> + * Remap swioltb memory in the unencrypted physical address space
> + * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
> + * Isolation VMs).
> + */
> +void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
> +{
> +       void *vaddr = NULL;
> +
> +       if (swiotlb_unencrypted_base) {
> +               phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
> +
> +               vaddr = memremap(paddr, bytes, MEMREMAP_WB);
> +               if (!vaddr)
> +                       pr_err("Failed to map the unencrypted memory %llx 
> size %lx.\n",
> +                              paddr, bytes);
> +       }
> +
> +       return vaddr;
> +}
> +
>   /*
>    * Early SWIOTLB allocation may be too early to allow an architecture to
>    * perform the desired operations.  This function allows the 
> architecture to
> @@ -172,7 +196,12 @@ void __init swiotlb_update_mem_attributes(void)
>          vaddr = phys_to_virt(mem->start);
>          bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
>          set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
> -       memset(vaddr, 0, bytes);
> +
> +       mem->vaddr = swiotlb_mem_remap(mem, bytes);
> +       if (!mem->vaddr)
> +               mem->vaddr = vaddr;
> +
> +       memset(mem->vaddr, 0, bytes);
>   }
> 
>   static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t 
> start,
> @@ -196,7 +225,17 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem 
> *mem, phys_addr_t start,
>                  mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
>                  mem->slots[i].alloc_size = 0;
>          }
> +
> +       /*
> +        * If swiotlb_unencrypted_base is set, the bounce buffer memory will
> +        * be remapped and cleared in swiotlb_update_mem_attributes.
> +        */
> +       if (swiotlb_unencrypted_base)
> +               return;
> +
>          memset(vaddr, 0, bytes);
> +       mem->vaddr = vaddr;
> +       return;
>   }
> 
>   int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int 
> verbose)
> @@ -371,7 +410,7 @@ 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, orig_addr_offset;
> 
>          if (orig_addr == INVALID_PHYS_ADDR)
> 
> 
> Thanks.
> 

Re: [PATCH V3 1/5] Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM

[Tom Lendacky]

On 12/3/21 1:11 PM, Tom Lendacky wrote:
> On 12/3/21 5:20 AM, Tianyu Lan wrote:
>> On 12/2/2021 10:42 PM, Tom Lendacky wrote:
>>> On 12/1/21 10:02 AM, 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.
>>>>
>>>> Expose swiotlb_unencrypted_base for platforms to set unencrypted
>>>> memory base offset and platform calls swiotlb_update_mem_attributes()
>>>> to remap swiotlb mem to unencrypted address space. memremap() can
>>>> not be called in the early stage and so put remapping code into
>>>> swiotlb_update_mem_attributes(). Store remap address and use it to copy
>>>> data from/to swiotlb bounce buffer.
>>>>
>>>> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
>>>
>>> This patch results in the following stack trace during a bare-metal boot
>>> on my EPYC system with SME active (e.g. mem_encrypt=on):
>>>
>>> [    0.123932] BUG: Bad page state in process swapper  pfn:108001
>>> [    0.123942] page:(____ptrval____) refcount:0 mapcount:-128 
>>> mapping:0000000000000000 index:0x0 pfn:0x108001
>>> [    0.123946] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
>>> [    0.123952] raw: 0017ffffc0000000 ffff88904f2d5e80 ffff88904f2d5e80 
>>> 0000000000000000
>>> [    0.123954] raw: 0000000000000000 0000000000000000 00000000ffffff7f 
>>> 0000000000000000
>>> [    0.123955] page dumped because: nonzero mapcount
>>> [    0.123957] Modules linked in:
>>> [    0.123961] CPU: 0 PID: 0 Comm: swapper Not tainted 
>>> 5.16.0-rc3-sos-custom #2
>>> [    0.123964] Hardware name: AMD Corporation
>>> [    0.123967] Call Trace:
>>> [    0.123971]  <TASK>
>>> [    0.123975]  dump_stack_lvl+0x48/0x5e
>>> [    0.123985]  bad_page.cold+0x65/0x96
>>> [    0.123990]  __free_pages_ok+0x3a8/0x410
>>> [    0.123996]  memblock_free_all+0x171/0x1dc
>>> [    0.124005]  mem_init+0x1f/0x14b
>>> [    0.124011]  start_kernel+0x3b5/0x6a1
>>> [    0.124016]  secondary_startup_64_no_verify+0xb0/0xbb
>>> [    0.124022]  </TASK>
>>>
>>> I see ~40 of these traces, each for different pfns.
>>>
>>> Thanks,
>>> Tom
>>
>> Hi Tom:
>>        Thanks for your test. Could you help to test the following patch 
>> and check whether it can fix the issue.
> 
> The patch is mangled. Is the only difference where set_memory_decrypted() 
> is called?

I de-mangled the patch. No more stack traces with SME active.

Thanks,
Tom

> 
> Thanks,
> Tom
> 
>>
>>
>> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
>> index 569272871375..f6c3638255d5 100644
>> --- a/include/linux/swiotlb.h
>> +++ b/include/linux/swiotlb.h
>> @@ -73,6 +73,9 @@ 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.
>> @@ -92,6 +95,7 @@ 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;
>> @@ -186,4 +190,6 @@ static inline bool is_swiotlb_for_alloc(struct 
>> device *dev)
>>   }
>>   #endif /* CONFIG_DMA_RESTRICTED_POOL */
>>
>> +extern phys_addr_t swiotlb_unencrypted_base;
>> +
>>   #endif /* __LINUX_SWIOTLB_H */
>> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
>> index 8e840fbbed7c..34e6ade4f73c 100644
>> --- a/kernel/dma/swiotlb.c
>> +++ b/kernel/dma/swiotlb.c
>> @@ -50,6 +50,7 @@
>>   #include <asm/io.h>
>>   #include <asm/dma.h>
>>
>> +#include <linux/io.h>
>>   #include <linux/init.h>
>>   #include <linux/memblock.h>
>>   #include <linux/iommu-helper.h>
>> @@ -72,6 +73,8 @@ enum swiotlb_force swiotlb_force;
>>
>>   struct io_tlb_mem io_tlb_default_mem;
>>
>> +phys_addr_t swiotlb_unencrypted_base;
>> +
>>   /*
>>    * Max segment that we can provide which (if pages are contingous) will
>>    * not be bounced (unless SWIOTLB_FORCE is set).
>> @@ -155,6 +158,27 @@ static inline unsigned long nr_slots(u64 val)
>>          return DIV_ROUND_UP(val, IO_TLB_SIZE);
>>   }
>>
>> +/*
>> + * Remap swioltb memory in the unencrypted physical address space
>> + * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
>> + * Isolation VMs).
>> + */
>> +void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
>> +{
>> +       void *vaddr = NULL;
>> +
>> +       if (swiotlb_unencrypted_base) {
>> +               phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
>> +
>> +               vaddr = memremap(paddr, bytes, MEMREMAP_WB);
>> +               if (!vaddr)
>> +                       pr_err("Failed to map the unencrypted memory 
>> %llx size %lx.\n",
>> +                              paddr, bytes);
>> +       }
>> +
>> +       return vaddr;
>> +}
>> +
>>   /*
>>    * Early SWIOTLB allocation may be too early to allow an architecture to
>>    * perform the desired operations.  This function allows the 
>> architecture to
>> @@ -172,7 +196,12 @@ void __init swiotlb_update_mem_attributes(void)
>>          vaddr = phys_to_virt(mem->start);
>>          bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
>>          set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
>> -       memset(vaddr, 0, bytes);
>> +
>> +       mem->vaddr = swiotlb_mem_remap(mem, bytes);
>> +       if (!mem->vaddr)
>> +               mem->vaddr = vaddr;
>> +
>> +       memset(mem->vaddr, 0, bytes);
>>   }
>>
>>   static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, 
>> phys_addr_t start,
>> @@ -196,7 +225,17 @@ static void swiotlb_init_io_tlb_mem(struct 
>> io_tlb_mem *mem, phys_addr_t start,
>>                  mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
>>                  mem->slots[i].alloc_size = 0;
>>          }
>> +
>> +       /*
>> +        * If swiotlb_unencrypted_base is set, the bounce buffer memory 
>> will
>> +        * be remapped and cleared in swiotlb_update_mem_attributes.
>> +        */
>> +       if (swiotlb_unencrypted_base)
>> +               return;
>> +
>>          memset(vaddr, 0, bytes);
>> +       mem->vaddr = vaddr;
>> +       return;
>>   }
>>
>>   int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int 
>> verbose)
>> @@ -371,7 +410,7 @@ 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, orig_addr_offset;
>>
>>          if (orig_addr == INVALID_PHYS_ADDR)
>>
>>
>> Thanks.
>>

Re: [PATCH V3 1/5] Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM

[Tianyu Lan]

On 12/4/2021 4:06 AM, Tom Lendacky wrote:
>>> Hi Tom:
>>>        Thanks for your test. Could you help to test the following 
>>> patch and check whether it can fix the issue.
>>
>> The patch is mangled. Is the only difference where 
>> set_memory_decrypted() is called?
> 
> I de-mangled the patch. No more stack traces with SME active.
> 
> Thanks,
> Tom

Hi Tom:
	Thanks a lot for your rework and test. I will update in the next version.

Thanks.

[PATCH V3 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hyper-V provides Isolation VM which has memory encrypt support. Add
hyperv_cc_platform_has() and return true for check of GUEST_MEM_ENCRYPT
attribute.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 arch/x86/kernel/cc_platform.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
index 03bb2f343ddb..f3bb0431f5c5 100644
--- a/arch/x86/kernel/cc_platform.c
+++ b/arch/x86/kernel/cc_platform.c
@@ -11,6 +11,7 @@
 #include <linux/cc_platform.h>
 #include <linux/mem_encrypt.h>
 
+#include <asm/mshyperv.h>
 #include <asm/processor.h>
 
 static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr)
@@ -58,9 +59,23 @@ static bool amd_cc_platform_has(enum cc_attr attr)
 #endif
 }
 
+static bool hyperv_cc_platform_has(enum cc_attr attr)
+{
+#ifdef CONFIG_HYPERV
+	if (attr == CC_ATTR_GUEST_MEM_ENCRYPT)
+		return true;
+	else
+		return false;
+#else
+	return false;
+#endif
+}
 
 bool cc_platform_has(enum cc_attr attr)
 {
+	if (hv_is_isolation_supported())
+		return hyperv_cc_platform_has(attr);
+
 	if (sme_me_mask)
 		return amd_cc_platform_has(attr);
 
-- 
2.25.1

Re: [PATCH V3 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Wei Liu]

On Wed, Dec 01, 2021 at 11:02:53AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> Hyper-V provides Isolation VM which has memory encrypt support. Add
> hyperv_cc_platform_has() and return true for check of GUEST_MEM_ENCRYPT
> attribute.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> ---
>  arch/x86/kernel/cc_platform.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
> index 03bb2f343ddb..f3bb0431f5c5 100644
> --- a/arch/x86/kernel/cc_platform.c
> +++ b/arch/x86/kernel/cc_platform.c
> @@ -11,6 +11,7 @@
>  #include <linux/cc_platform.h>
>  #include <linux/mem_encrypt.h>
>  
> +#include <asm/mshyperv.h>
>  #include <asm/processor.h>
>  
>  static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr)
> @@ -58,9 +59,23 @@ static bool amd_cc_platform_has(enum cc_attr attr)
>  #endif
>  }
>  
> +static bool hyperv_cc_platform_has(enum cc_attr attr)
> +{
> +#ifdef CONFIG_HYPERV
> +	if (attr == CC_ATTR_GUEST_MEM_ENCRYPT)
> +		return true;
> +	else
> +		return false;

This can be simplified as

	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;


Wei.

Re: [PATCH V3 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Tianyu Lan]

On 12/2/2021 10:39 PM, Wei Liu wrote:
>> +static bool hyperv_cc_platform_has(enum cc_attr attr)
>> +{
>> +#ifdef CONFIG_HYPERV
>> +	if (attr == CC_ATTR_GUEST_MEM_ENCRYPT)
>> +		return true;
>> +	else
>> +		return false;
> This can be simplified as
> 
> 	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;
> 
> 
> Wei.

Hi Wei:	
	Thanks for your review. Will update.

[PATCH V3 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

hyperv Isolation VM requires bounce buffer support to copy
data from/to encrypted memory and so enable swiotlb force
mode to use swiotlb bounce buffer for DMA transaction.

In Isolation VM with AMD SEV, the 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.

Hyper-V initalizes swiotlb bounce buffer and default swiotlb
needs to be disabled. pci_swiotlb_detect_override() and
pci_swiotlb_detect_4gb() enable the default one. To override
the setting, hyperv_swiotlb_detect() needs to run before
these detect functions which depends on the pci_xen_swiotlb_
init(). Make pci_xen_swiotlb_init() depends on the hyperv_swiotlb
_detect() to keep the order.

Swiotlb bounce buffer code calls set_memory_decrypted()
to mark bounce buffer visible to host and map it in extra
address space via memremap. Populate the shared_gpa_boundary
(vTOM) via swiotlb_unencrypted_base variable.

The map function memremap() can't work in the early place
hyperv_iommu_swiotlb_init() and so call swiotlb_update_mem_attributes()
in the hyperv_iommu_swiotlb_later_init().

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 arch/x86/xen/pci-swiotlb-xen.c |  3 +-
 drivers/hv/vmbus_drv.c         |  3 ++
 drivers/iommu/hyperv-iommu.c   | 56 ++++++++++++++++++++++++++++++++++
 include/linux/hyperv.h         |  8 +++++
 4 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
index 46df59aeaa06..30fd0600b008 100644
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ b/arch/x86/xen/pci-swiotlb-xen.c
@@ -4,6 +4,7 @@
 
 #include <linux/dma-map-ops.h>
 #include <linux/pci.h>
+#include <linux/hyperv.h>
 #include <xen/swiotlb-xen.h>
 
 #include <asm/xen/hypervisor.h>
@@ -91,6 +92,6 @@ int pci_xen_swiotlb_init_late(void)
 EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
 
 IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
-		  NULL,
+		  hyperv_swiotlb_detect,
 		  pci_xen_swiotlb_init,
 		  NULL);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 392c1ac4f819..0a64ccfafb8b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -33,6 +33,7 @@
 #include <linux/random.h>
 #include <linux/kernel.h>
 #include <linux/syscore_ops.h>
+#include <linux/dma-map-ops.h>
 #include <clocksource/hyperv_timer.h>
 #include "hyperv_vmbus.h"
 
@@ -2078,6 +2079,7 @@ struct hv_device *vmbus_device_create(const guid_t *type,
 	return child_device_obj;
 }
 
+static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
 /*
  * vmbus_device_register - Register the child device
  */
@@ -2118,6 +2120,7 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 	}
 	hv_debug_add_dev_dir(child_device_obj);
 
+	child_device_obj->device.dma_mask = &vmbus_dma_mask;
 	return 0;
 
 err_kset_unregister:
diff --git a/drivers/iommu/hyperv-iommu.c b/drivers/iommu/hyperv-iommu.c
index e285a220c913..dd729d49a1eb 100644
--- a/drivers/iommu/hyperv-iommu.c
+++ b/drivers/iommu/hyperv-iommu.c
@@ -13,14 +13,20 @@
 #include <linux/irq.h>
 #include <linux/iommu.h>
 #include <linux/module.h>
+#include <linux/hyperv.h>
+#include <linux/io.h>
 
 #include <asm/apic.h>
 #include <asm/cpu.h>
 #include <asm/hw_irq.h>
 #include <asm/io_apic.h>
+#include <asm/iommu.h>
+#include <asm/iommu_table.h>
 #include <asm/irq_remapping.h>
 #include <asm/hypervisor.h>
 #include <asm/mshyperv.h>
+#include <asm/swiotlb.h>
+#include <linux/dma-direct.h>
 
 #include "irq_remapping.h"
 
@@ -337,4 +343,54 @@ static const struct irq_domain_ops hyperv_root_ir_domain_ops = {
 	.free = hyperv_root_irq_remapping_free,
 };
 
+static void __init hyperv_iommu_swiotlb_init(void)
+{
+	unsigned long hyperv_io_tlb_size;
+	void *hyperv_io_tlb_start;
+
+	/*
+	 * Allocate Hyper-V swiotlb bounce buffer at early place
+	 * to reserve large contiguous memory.
+	 */
+	hyperv_io_tlb_size = swiotlb_size_or_default();
+	hyperv_io_tlb_start = memblock_alloc(hyperv_io_tlb_size, PAGE_SIZE);
+
+	if (!hyperv_io_tlb_start)
+		pr_warn("Fail to allocate Hyper-V swiotlb buffer.\n");
+
+	swiotlb_init_with_tbl(hyperv_io_tlb_start,
+			      hyperv_io_tlb_size >> IO_TLB_SHIFT, true);
+}
+
+int __init hyperv_swiotlb_detect(void)
+{
+	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
+		return 0;
+
+	if (!hv_is_isolation_supported())
+		return 0;
+
+	/*
+	 * Enable swiotlb force mode in Isolation VM to
+	 * use swiotlb bounce buffer for dma transaction.
+	 */
+	if (hv_isolation_type_snp())
+		swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary;
+	swiotlb_force = SWIOTLB_FORCE;
+	return 1;
+}
+
+static void __init hyperv_iommu_swiotlb_later_init(void)
+{
+	/*
+	 * Swiotlb bounce buffer needs to be mapped in extra address
+	 * space. Map function doesn't work in the early place and so
+	 * call swiotlb_update_mem_attributes() here.
+	 */
+	swiotlb_update_mem_attributes();
+}
+
+IOMMU_INIT_FINISH(hyperv_swiotlb_detect,
+		  NULL, hyperv_iommu_swiotlb_init,
+		  hyperv_iommu_swiotlb_later_init);
 #endif
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index b823311eac79..1f037e114dc8 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1726,6 +1726,14 @@ int hyperv_write_cfg_blk(struct pci_dev *dev, void *buf, unsigned int len,
 int hyperv_reg_block_invalidate(struct pci_dev *dev, void *context,
 				void (*block_invalidate)(void *context,
 							 u64 block_mask));
+#if IS_ENABLED(CONFIG_HYPERV)
+int __init hyperv_swiotlb_detect(void);
+#else
+static inline int __init hyperv_swiotlb_detect(void)
+{
+	return 0;
+}
+#endif
 
 struct hyperv_pci_block_ops {
 	int (*read_block)(struct pci_dev *dev, void *buf, unsigned int buf_len,
-- 
2.25.1

Re: [PATCH V3 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM

[Wei Liu]

On Wed, Dec 01, 2021 at 11:02:54AM -0500, Tianyu Lan wrote:
[...]
> diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
> index 46df59aeaa06..30fd0600b008 100644
> --- a/arch/x86/xen/pci-swiotlb-xen.c
> +++ b/arch/x86/xen/pci-swiotlb-xen.c
> @@ -4,6 +4,7 @@
>  
>  #include <linux/dma-map-ops.h>
>  #include <linux/pci.h>
> +#include <linux/hyperv.h>
>  #include <xen/swiotlb-xen.h>
>  
>  #include <asm/xen/hypervisor.h>
> @@ -91,6 +92,6 @@ int pci_xen_swiotlb_init_late(void)
>  EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
>  
>  IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
> -		  NULL,
> +		  hyperv_swiotlb_detect,

It is not immediately obvious why this is needed just by reading the
code. Please consider copying some of the text in the commit message to
a comment here.

Thanks,
Wei.

Re: [PATCH V3 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM

[Tianyu Lan]

On 12/2/2021 10:43 PM, Wei Liu wrote:
> On Wed, Dec 01, 2021 at 11:02:54AM -0500, Tianyu Lan wrote:
> [...]
>> diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
>> index 46df59aeaa06..30fd0600b008 100644
>> --- a/arch/x86/xen/pci-swiotlb-xen.c
>> +++ b/arch/x86/xen/pci-swiotlb-xen.c
>> @@ -4,6 +4,7 @@
>>   
>>   #include <linux/dma-map-ops.h>
>>   #include <linux/pci.h>
>> +#include <linux/hyperv.h>
>>   #include <xen/swiotlb-xen.h>
>>   
>>   #include <asm/xen/hypervisor.h>
>> @@ -91,6 +92,6 @@ int pci_xen_swiotlb_init_late(void)
>>   EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
>>   
>>   IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
>> -		  NULL,
>> +		  hyperv_swiotlb_detect,
> 
> It is not immediately obvious why this is needed just by reading the
> code. Please consider copying some of the text in the commit message to
> a comment here.
> 

Thanks for suggestion. Will update.

RE: [PATCH V3 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM

[Michael Kelley (LINUX)]

From: Tianyu Lan <ltykernel@gmail.com> Sent: Wednesday, December 1, 2021 8:03 AM
> 
> hyperv Isolation VM requires bounce buffer support to copy
> data from/to encrypted memory and so enable swiotlb force
> mode to use swiotlb bounce buffer for DMA transaction.
> 
> In Isolation VM with AMD SEV, the 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.
> 
> Hyper-V initalizes swiotlb bounce buffer and default swiotlb
> needs to be disabled. pci_swiotlb_detect_override() and
> pci_swiotlb_detect_4gb() enable the default one. To override
> the setting, hyperv_swiotlb_detect() needs to run before
> these detect functions which depends on the pci_xen_swiotlb_
> init(). Make pci_xen_swiotlb_init() depends on the hyperv_swiotlb
> _detect() to keep the order.
> 
> Swiotlb bounce buffer code calls set_memory_decrypted()
> to mark bounce buffer visible to host and map it in extra
> address space via memremap. Populate the shared_gpa_boundary
> (vTOM) via swiotlb_unencrypted_base variable.
> 
> The map function memremap() can't work in the early place
> hyperv_iommu_swiotlb_init() and so call swiotlb_update_mem_attributes()
> in the hyperv_iommu_swiotlb_later_init().
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> ---
>  arch/x86/xen/pci-swiotlb-xen.c |  3 +-
>  drivers/hv/vmbus_drv.c         |  3 ++
>  drivers/iommu/hyperv-iommu.c   | 56 ++++++++++++++++++++++++++++++++++
>  include/linux/hyperv.h         |  8 +++++
>  4 files changed, 69 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
> index 46df59aeaa06..30fd0600b008 100644
> --- a/arch/x86/xen/pci-swiotlb-xen.c
> +++ b/arch/x86/xen/pci-swiotlb-xen.c
> @@ -4,6 +4,7 @@
> 
>  #include <linux/dma-map-ops.h>
>  #include <linux/pci.h>
> +#include <linux/hyperv.h>
>  #include <xen/swiotlb-xen.h>
> 
>  #include <asm/xen/hypervisor.h>
> @@ -91,6 +92,6 @@ int pci_xen_swiotlb_init_late(void)
>  EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
> 
>  IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
> -		  NULL,
> +		  hyperv_swiotlb_detect,
>  		  pci_xen_swiotlb_init,
>  		  NULL);
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 392c1ac4f819..0a64ccfafb8b 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -33,6 +33,7 @@
>  #include <linux/random.h>
>  #include <linux/kernel.h>
>  #include <linux/syscore_ops.h>
> +#include <linux/dma-map-ops.h>
>  #include <clocksource/hyperv_timer.h>
>  #include "hyperv_vmbus.h"
> 
> @@ -2078,6 +2079,7 @@ struct hv_device *vmbus_device_create(const guid_t *type,
>  	return child_device_obj;
>  }
> 
> +static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
>  /*
>   * vmbus_device_register - Register the child device
>   */
> @@ -2118,6 +2120,7 @@ int vmbus_device_register(struct hv_device *child_device_obj)
>  	}
>  	hv_debug_add_dev_dir(child_device_obj);
> 
> +	child_device_obj->device.dma_mask = &vmbus_dma_mask;
>  	return 0;
> 
>  err_kset_unregister:
> diff --git a/drivers/iommu/hyperv-iommu.c b/drivers/iommu/hyperv-iommu.c
> index e285a220c913..dd729d49a1eb 100644
> --- a/drivers/iommu/hyperv-iommu.c
> +++ b/drivers/iommu/hyperv-iommu.c
> @@ -13,14 +13,20 @@
>  #include <linux/irq.h>
>  #include <linux/iommu.h>
>  #include <linux/module.h>
> +#include <linux/hyperv.h>
> +#include <linux/io.h>
> 
>  #include <asm/apic.h>
>  #include <asm/cpu.h>
>  #include <asm/hw_irq.h>
>  #include <asm/io_apic.h>
> +#include <asm/iommu.h>
> +#include <asm/iommu_table.h>
>  #include <asm/irq_remapping.h>
>  #include <asm/hypervisor.h>
>  #include <asm/mshyperv.h>
> +#include <asm/swiotlb.h>
> +#include <linux/dma-direct.h>
> 
>  #include "irq_remapping.h"
> 
> @@ -337,4 +343,54 @@ static const struct irq_domain_ops hyperv_root_ir_domain_ops = {
>  	.free = hyperv_root_irq_remapping_free,
>  };
> 
> +static void __init hyperv_iommu_swiotlb_init(void)
> +{
> +	unsigned long hyperv_io_tlb_size;
> +	void *hyperv_io_tlb_start;
> +
> +	/*
> +	 * Allocate Hyper-V swiotlb bounce buffer at early place
> +	 * to reserve large contiguous memory.
> +	 */
> +	hyperv_io_tlb_size = swiotlb_size_or_default();
> +	hyperv_io_tlb_start = memblock_alloc(hyperv_io_tlb_size, PAGE_SIZE);
> +
> +	if (!hyperv_io_tlb_start)
> +		pr_warn("Fail to allocate Hyper-V swiotlb buffer.\n");

In the error case, won't swiotlb_init_with_tlb() end up panic'ing when
it tries to zero out the memory?   The only real choice here is to
return immediately after printing the message, and not call
swiotlb_init_with_tlb().

> +
> +	swiotlb_init_with_tbl(hyperv_io_tlb_start,
> +			      hyperv_io_tlb_size >> IO_TLB_SHIFT, true);
> +}
> +
> +int __init hyperv_swiotlb_detect(void)
> +{
> +	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
> +		return 0;
> +
> +	if (!hv_is_isolation_supported())
> +		return 0;
> +
> +	/*
> +	 * Enable swiotlb force mode in Isolation VM to
> +	 * use swiotlb bounce buffer for dma transaction.
> +	 */
> +	if (hv_isolation_type_snp())
> +		swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary;
> +	swiotlb_force = SWIOTLB_FORCE;
> +	return 1;
> +}
> +
> +static void __init hyperv_iommu_swiotlb_later_init(void)
> +{
> +	/*
> +	 * Swiotlb bounce buffer needs to be mapped in extra address
> +	 * space. Map function doesn't work in the early place and so
> +	 * call swiotlb_update_mem_attributes() here.
> +	 */
> +	swiotlb_update_mem_attributes();
> +}
> +
> +IOMMU_INIT_FINISH(hyperv_swiotlb_detect,
> +		  NULL, hyperv_iommu_swiotlb_init,
> +		  hyperv_iommu_swiotlb_later_init);
>  #endif
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index b823311eac79..1f037e114dc8 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1726,6 +1726,14 @@ int hyperv_write_cfg_blk(struct pci_dev *dev, void *buf, unsigned int len,
>  int hyperv_reg_block_invalidate(struct pci_dev *dev, void *context,
>  				void (*block_invalidate)(void *context,
>  							 u64 block_mask));
> +#if IS_ENABLED(CONFIG_HYPERV)
> +int __init hyperv_swiotlb_detect(void);
> +#else
> +static inline int __init hyperv_swiotlb_detect(void)
> +{
> +	return 0;
> +}
> +#endif
> 
>  struct hyperv_pci_block_ops {
>  	int (*read_block)(struct pci_dev *dev, void *buf, unsigned int buf_len,
> --
> 2.25.1

Re: [PATCH V3 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM

[Tianyu Lan]

On 12/4/2021 3:17 AM, Michael Kelley (LINUX) wrote:
>> +static void __init hyperv_iommu_swiotlb_init(void)
>> +{
>> +	unsigned long hyperv_io_tlb_size;
>> +	void *hyperv_io_tlb_start;
>> +
>> +	/*
>> +	 * Allocate Hyper-V swiotlb bounce buffer at early place
>> +	 * to reserve large contiguous memory.
>> +	 */
>> +	hyperv_io_tlb_size = swiotlb_size_or_default();
>> +	hyperv_io_tlb_start = memblock_alloc(hyperv_io_tlb_size, PAGE_SIZE);
>> +
>> +	if (!hyperv_io_tlb_start)
>> +		pr_warn("Fail to allocate Hyper-V swiotlb buffer.\n");
> In the error case, won't swiotlb_init_with_tlb() end up panic'ing when
> it tries to zero out the memory?   The only real choice here is to
> return immediately after printing the message, and not call
> swiotlb_init_with_tlb().
> 

Yes, agree. Will update.

[PATCH V3 4/5] scsi: storvsc: Add Isolation VM support for storvsc driver

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

In Isolation VM, all shared memory with host needs to mark visible
to host via hvcall. vmbus_establish_gpadl() has already done it for
storvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_
mpb_desc() still needs to be handled. Use DMA API(scsi_dma_map/unmap)
to map these memory during sending/receiving packet and return swiotlb
bounce buffer dma address. In Isolation VM, swiotlb  bounce buffer is
marked to be visible to host and the swiotlb force mode is enabled.

Set device's dma min align mask to HV_HYP_PAGE_SIZE - 1 in order to
keep the original data offset in the bounce buffer.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 drivers/hv/vmbus_drv.c     |  1 +
 drivers/scsi/storvsc_drv.c | 37 +++++++++++++++++++++----------------
 include/linux/hyperv.h     |  1 +
 3 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 0a64ccfafb8b..ae6ec503399a 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2121,6 +2121,7 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 	hv_debug_add_dev_dir(child_device_obj);
 
 	child_device_obj->device.dma_mask = &vmbus_dma_mask;
+	child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
 	return 0;
 
 err_kset_unregister:
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 20595c0ba0ae..ae293600d799 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -21,6 +21,8 @@
 #include <linux/device.h>
 #include <linux/hyperv.h>
 #include <linux/blkdev.h>
+#include <linux/dma-mapping.h>
+
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>
@@ -1336,6 +1338,7 @@ static void storvsc_on_channel_callback(void *context)
 					continue;
 				}
 				request = (struct storvsc_cmd_request *)scsi_cmd_priv(scmnd);
+				scsi_dma_unmap(scmnd);
 			}
 
 			storvsc_on_receive(stor_device, packet, request);
@@ -1749,7 +1752,6 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 	struct hv_host_device *host_dev = shost_priv(host);
 	struct hv_device *dev = host_dev->dev;
 	struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
-	int i;
 	struct scatterlist *sgl;
 	unsigned int sg_count;
 	struct vmscsi_request *vm_srb;
@@ -1831,10 +1833,11 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 	payload_sz = sizeof(cmd_request->mpb);
 
 	if (sg_count) {
-		unsigned int hvpgoff, hvpfns_to_add;
 		unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset);
 		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
-		u64 hvpfn;
+		struct scatterlist *sg;
+		unsigned long hvpfn, hvpfns_to_add;
+		int j, i = 0;
 
 		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
 
@@ -1848,21 +1851,22 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 		payload->range.len = length;
 		payload->range.offset = offset_in_hvpg;
 
+		sg_count = scsi_dma_map(scmnd);
+		if (sg_count < 0)
+			return SCSI_MLQUEUE_DEVICE_BUSY;
 
-		for (i = 0; sgl != NULL; sgl = sg_next(sgl)) {
+		for_each_sg(sgl, sg, sg_count, j) {
 			/*
-			 * Init values for the current sgl entry. hvpgoff
-			 * and hvpfns_to_add are in units of Hyper-V size
-			 * pages. Handling the PAGE_SIZE != HV_HYP_PAGE_SIZE
-			 * case also handles values of sgl->offset that are
-			 * larger than PAGE_SIZE. Such offsets are handled
-			 * even on other than the first sgl entry, provided
-			 * they are a multiple of PAGE_SIZE.
+			 * Init values for the current sgl entry. hvpfns_to_add
+			 * is in units of Hyper-V size pages. Handling the
+			 * PAGE_SIZE != HV_HYP_PAGE_SIZE case also handles
+			 * values of sgl->offset that are larger than PAGE_SIZE.
+			 * Such offsets are handled even on other than the first
+			 * sgl entry, provided they are a multiple of PAGE_SIZE.
 			 */
-			hvpgoff = HVPFN_DOWN(sgl->offset);
-			hvpfn = page_to_hvpfn(sg_page(sgl)) + hvpgoff;
-			hvpfns_to_add =	HVPFN_UP(sgl->offset + sgl->length) -
-						hvpgoff;
+			hvpfn = HVPFN_DOWN(sg_dma_address(sg));
+			hvpfns_to_add = HVPFN_UP(sg_dma_address(sg) +
+						 sg_dma_len(sg)) - hvpfn;
 
 			/*
 			 * Fill the next portion of the PFN array with
@@ -1872,7 +1876,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 			 * the PFN array is filled.
 			 */
 			while (hvpfns_to_add--)
-				payload->range.pfn_array[i++] =	hvpfn++;
+				payload->range.pfn_array[i++] = hvpfn++;
 		}
 	}
 
@@ -2016,6 +2020,7 @@ static int storvsc_probe(struct hv_device *device,
 	stor_device->vmscsi_size_delta = sizeof(struct vmscsi_win8_extension);
 	spin_lock_init(&stor_device->lock);
 	hv_set_drvdata(device, stor_device);
+	dma_set_min_align_mask(&device->device, HV_HYP_PAGE_SIZE - 1);
 
 	stor_device->port_number = host->host_no;
 	ret = storvsc_connect_to_vsp(device, storvsc_ringbuffer_size, is_fc);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 1f037e114dc8..74f5e92f91a0 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1261,6 +1261,7 @@ struct hv_device {
 
 	struct vmbus_channel *channel;
 	struct kset	     *channels_kset;
+	struct device_dma_parameters dma_parms;
 
 	/* place holder to keep track of the dir for hv device in debugfs */
 	struct dentry *debug_dir;
-- 
2.25.1

[PATCH V3 5/5] hv_netvsc: Add Isolation VM support for netvsc driver

[Tianyu Lan]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

In Isolation VM, all shared memory with host needs to mark visible
to host via hvcall. vmbus_establish_gpadl() has already done it for
netvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_
pagebuffer() stills need to be handled. Use DMA API to map/umap
these memory during sending/receiving packet and Hyper-V swiotlb
bounce buffer dma adress will be returned. The swiotlb bounce buffer
has been masked to be visible to host during boot up.

rx/tx ring buffer is allocated via vzalloc() and they need to be
mapped into unencrypted address space(above vTOM) before sharing
with host and accessing. Add hv_map/unmap_memory() to map/umap rx
/tx ring buffer.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v2:
       * Add hv_map/unmap_memory() to map/umap rx/tx ring buffer.
---
 arch/x86/hyperv/ivm.c             |  28 ++++++
 drivers/hv/hv_common.c            |  11 +++
 drivers/net/hyperv/hyperv_net.h   |   5 ++
 drivers/net/hyperv/netvsc.c       | 136 +++++++++++++++++++++++++++++-
 drivers/net/hyperv/netvsc_drv.c   |   1 +
 drivers/net/hyperv/rndis_filter.c |   2 +
 include/asm-generic/mshyperv.h    |   2 +
 include/linux/hyperv.h            |   5 ++
 8 files changed, 187 insertions(+), 3 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 69c7a57f3307..9f78d8f67ea3 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -287,3 +287,31 @@ int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visibl
 	kfree(pfn_array);
 	return ret;
 }
+
+/*
+ * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM.
+ */
+void *hv_map_memory(void *addr, unsigned long size)
+{
+	unsigned long *pfns = kcalloc(size / HV_HYP_PAGE_SIZE,
+				      sizeof(unsigned long), GFP_KERNEL);
+	void *vaddr;
+	int i;
+
+	if (!pfns)
+		return NULL;
+
+	for (i = 0; i < size / PAGE_SIZE; i++)
+		pfns[i] = virt_to_hvpfn(addr + i * PAGE_SIZE) +
+			(ms_hyperv.shared_gpa_boundary >> PAGE_SHIFT);
+
+	vaddr = vmap_pfn(pfns, size / PAGE_SIZE, PAGE_KERNEL_IO);
+	kfree(pfns);
+
+	return vaddr;
+}
+
+void hv_unmap_memory(void *addr)
+{
+	vunmap(addr);
+}
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 7be173a99f27..3c5cb1f70319 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -295,3 +295,14 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_s
 	return HV_STATUS_INVALID_PARAMETER;
 }
 EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
+
+void __weak *hv_map_memory(void *addr, unsigned long size)
+{
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(hv_map_memory);
+
+void __weak hv_unmap_memory(void *addr)
+{
+}
+EXPORT_SYMBOL_GPL(hv_unmap_memory);
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 315278a7cf88..cf69da0e296c 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -164,6 +164,7 @@ struct hv_netvsc_packet {
 	u32 total_bytes;
 	u32 send_buf_index;
 	u32 total_data_buflen;
+	struct hv_dma_range *dma_range;
 };
 
 #define NETVSC_HASH_KEYLEN 40
@@ -1074,6 +1075,7 @@ struct netvsc_device {
 
 	/* Receive buffer allocated by us but manages by NetVSP */
 	void *recv_buf;
+	void *recv_original_buf;
 	u32 recv_buf_size; /* allocated bytes */
 	struct vmbus_gpadl recv_buf_gpadl_handle;
 	u32 recv_section_cnt;
@@ -1082,6 +1084,7 @@ struct netvsc_device {
 
 	/* Send buffer allocated by us */
 	void *send_buf;
+	void *send_original_buf;
 	u32 send_buf_size;
 	struct vmbus_gpadl send_buf_gpadl_handle;
 	u32 send_section_cnt;
@@ -1731,4 +1734,6 @@ struct rndis_message {
 #define RETRY_US_HI	10000
 #define RETRY_MAX	2000	/* >10 sec */
 
+void netvsc_dma_unmap(struct hv_device *hv_dev,
+		      struct hv_netvsc_packet *packet);
 #endif /* _HYPERV_NET_H */
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 396bc1c204e6..b7ade735a806 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -153,8 +153,21 @@ static void free_netvsc_device(struct rcu_head *head)
 	int i;
 
 	kfree(nvdev->extension);
-	vfree(nvdev->recv_buf);
-	vfree(nvdev->send_buf);
+
+	if (nvdev->recv_original_buf) {
+		hv_unmap_memory(nvdev->recv_buf);
+		vfree(nvdev->recv_original_buf);
+	} else {
+		vfree(nvdev->recv_buf);
+	}
+
+	if (nvdev->send_original_buf) {
+		hv_unmap_memory(nvdev->send_buf);
+		vfree(nvdev->send_original_buf);
+	} else {
+		vfree(nvdev->send_buf);
+	}
+
 	kfree(nvdev->send_section_map);
 
 	for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
@@ -338,6 +351,7 @@ static int netvsc_init_buf(struct hv_device *device,
 	unsigned int buf_size;
 	size_t map_words;
 	int i, ret = 0;
+	void *vaddr;
 
 	/* Get receive buffer area. */
 	buf_size = device_info->recv_sections * device_info->recv_section_size;
@@ -373,6 +387,17 @@ static int netvsc_init_buf(struct hv_device *device,
 		goto cleanup;
 	}
 
+	if (hv_isolation_type_snp()) {
+		vaddr = hv_map_memory(net_device->recv_buf, buf_size);
+		if (!vaddr) {
+			ret = -ENOMEM;
+			goto cleanup;
+		}
+
+		net_device->recv_original_buf = net_device->recv_buf;
+		net_device->recv_buf = vaddr;
+	}
+
 	/* Notify the NetVsp of the gpadl handle */
 	init_packet = &net_device->channel_init_pkt;
 	memset(init_packet, 0, sizeof(struct nvsp_message));
@@ -476,6 +501,17 @@ static int netvsc_init_buf(struct hv_device *device,
 		goto cleanup;
 	}
 
+	if (hv_isolation_type_snp()) {
+		vaddr = hv_map_memory(net_device->send_buf, buf_size);
+		if (!vaddr) {
+			ret = -ENOMEM;
+			goto cleanup;
+		}
+
+		net_device->send_original_buf = net_device->send_buf;
+		net_device->send_buf = vaddr;
+	}
+
 	/* Notify the NetVsp of the gpadl handle */
 	init_packet = &net_device->channel_init_pkt;
 	memset(init_packet, 0, sizeof(struct nvsp_message));
@@ -766,7 +802,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
 
 	/* Notify the layer above us */
 	if (likely(skb)) {
-		const struct hv_netvsc_packet *packet
+		struct hv_netvsc_packet *packet
 			= (struct hv_netvsc_packet *)skb->cb;
 		u32 send_index = packet->send_buf_index;
 		struct netvsc_stats *tx_stats;
@@ -782,6 +818,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
 		tx_stats->bytes += packet->total_bytes;
 		u64_stats_update_end(&tx_stats->syncp);
 
+		netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
 		napi_consume_skb(skb, budget);
 	}
 
@@ -946,6 +983,88 @@ static void netvsc_copy_to_send_buf(struct netvsc_device *net_device,
 		memset(dest, 0, padding);
 }
 
+void netvsc_dma_unmap(struct hv_device *hv_dev,
+		      struct hv_netvsc_packet *packet)
+{
+	u32 page_count = packet->cp_partial ?
+		packet->page_buf_cnt - packet->rmsg_pgcnt :
+		packet->page_buf_cnt;
+	int i;
+
+	if (!hv_is_isolation_supported())
+		return;
+
+	if (!packet->dma_range)
+		return;
+
+	for (i = 0; i < page_count; i++)
+		dma_unmap_single(&hv_dev->device, packet->dma_range[i].dma,
+				 packet->dma_range[i].mapping_size,
+				 DMA_TO_DEVICE);
+
+	kfree(packet->dma_range);
+}
+
+/* netvsc_dma_map - Map swiotlb bounce buffer with data page of
+ * packet sent by vmbus_sendpacket_pagebuffer() in the Isolation
+ * VM.
+ *
+ * In isolation VM, netvsc send buffer has been marked visible to
+ * host and so the data copied to send buffer doesn't need to use
+ * bounce buffer. The data pages handled by vmbus_sendpacket_pagebuffer()
+ * may not be copied to send buffer and so these pages need to be
+ * mapped with swiotlb bounce buffer. netvsc_dma_map() is to do
+ * that. The pfns in the struct hv_page_buffer need to be converted
+ * to bounce buffer's pfn. The loop here is necessary because the
+ * entries in the page buffer array are not necessarily full
+ * pages of data.  Each entry in the array has a separate offset and
+ * len that may be non-zero, even for entries in the middle of the
+ * array.  And the entries are not physically contiguous.  So each
+ * entry must be individually mapped rather than as a contiguous unit.
+ * So not use dma_map_sg() here.
+ */
+int netvsc_dma_map(struct hv_device *hv_dev,
+		   struct hv_netvsc_packet *packet,
+		   struct hv_page_buffer *pb)
+{
+	u32 page_count =  packet->cp_partial ?
+		packet->page_buf_cnt - packet->rmsg_pgcnt :
+		packet->page_buf_cnt;
+	dma_addr_t dma;
+	int i;
+
+	if (!hv_is_isolation_supported())
+		return 0;
+
+	packet->dma_range = kcalloc(page_count,
+				    sizeof(*packet->dma_range),
+				    GFP_KERNEL);
+	if (!packet->dma_range)
+		return -ENOMEM;
+
+	for (i = 0; i < page_count; i++) {
+		char *src = phys_to_virt((pb[i].pfn << HV_HYP_PAGE_SHIFT)
+					 + pb[i].offset);
+		u32 len = pb[i].len;
+
+		dma = dma_map_single(&hv_dev->device, src, len,
+				     DMA_TO_DEVICE);
+		if (dma_mapping_error(&hv_dev->device, dma)) {
+			kfree(packet->dma_range);
+			return -ENOMEM;
+		}
+
+		/* pb[].offset and pb[].len are not changed during dma mapping
+		 * and so not reassign.
+		 */
+		packet->dma_range[i].dma = dma;
+		packet->dma_range[i].mapping_size = len;
+		pb[i].pfn = dma >> HV_HYP_PAGE_SHIFT;
+	}
+
+	return 0;
+}
+
 static inline int netvsc_send_pkt(
 	struct hv_device *device,
 	struct hv_netvsc_packet *packet,
@@ -986,14 +1105,24 @@ static inline int netvsc_send_pkt(
 
 	trace_nvsp_send_pkt(ndev, out_channel, rpkt);
 
+	packet->dma_range = NULL;
 	if (packet->page_buf_cnt) {
 		if (packet->cp_partial)
 			pb += packet->rmsg_pgcnt;
 
+		ret = netvsc_dma_map(ndev_ctx->device_ctx, packet, pb);
+		if (ret) {
+			ret = -EAGAIN;
+			goto exit;
+		}
+
 		ret = vmbus_sendpacket_pagebuffer(out_channel,
 						  pb, packet->page_buf_cnt,
 						  &nvmsg, sizeof(nvmsg),
 						  req_id);
+
+		if (ret)
+			netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
 	} else {
 		ret = vmbus_sendpacket(out_channel,
 				       &nvmsg, sizeof(nvmsg),
@@ -1001,6 +1130,7 @@ static inline int netvsc_send_pkt(
 				       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	}
 
+exit:
 	if (ret == 0) {
 		atomic_inc_return(&nvchan->queue_sends);
 
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 7e66ae1d2a59..17958533bf30 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2512,6 +2512,7 @@ static int netvsc_probe(struct hv_device *dev,
 	net->netdev_ops = &device_ops;
 	net->ethtool_ops = &ethtool_ops;
 	SET_NETDEV_DEV(net, &dev->device);
+	dma_set_min_align_mask(&dev->device, HV_HYP_PAGE_SIZE - 1);
 
 	/* We always need headroom for rndis header */
 	net->needed_headroom = RNDIS_AND_PPI_SIZE;
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index f6c9c2a670f9..448fcc325ed7 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -361,6 +361,8 @@ static void rndis_filter_receive_response(struct net_device *ndev,
 			}
 		}
 
+		netvsc_dma_unmap(((struct net_device_context *)
+			netdev_priv(ndev))->device_ctx, &request->pkt);
 		complete(&request->wait_event);
 	} else {
 		netdev_err(ndev,
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 3e2248ac328e..94e73ba129c5 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -269,6 +269,8 @@ bool hv_isolation_type_snp(void);
 u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);
 void hyperv_cleanup(void);
 bool hv_query_ext_cap(u64 cap_query);
+void *hv_map_memory(void *addr, unsigned long size);
+void hv_unmap_memory(void *addr);
 #else /* CONFIG_HYPERV */
 static inline bool hv_is_hyperv_initialized(void) { return false; }
 static inline bool hv_is_hibernation_supported(void) { return false; }
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 74f5e92f91a0..b53cfc4163af 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1584,6 +1584,11 @@ struct hyperv_service_callback {
 	void (*callback)(void *context);
 };
 
+struct hv_dma_range {
+	dma_addr_t dma;
+	u32 mapping_size;
+};
+
 #define MAX_SRV_VER	0x7ffffff
 extern bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf, u32 buflen,
 				const int *fw_version, int fw_vercnt,
-- 
2.25.1

RE: [PATCH V3 5/5] hv_netvsc: Add Isolation VM support for netvsc driver

[Michael Kelley (LINUX)]

From: Tianyu Lan <ltykernel@gmail.com> Sent: Wednesday, December 1, 2021 8:03 AM
> 
> In Isolation VM, all shared memory with host needs to mark visible
> to host via hvcall. vmbus_establish_gpadl() has already done it for
> netvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_
> pagebuffer() stills need to be handled. Use DMA API to map/umap
> these memory during sending/receiving packet and Hyper-V swiotlb
> bounce buffer dma adress will be returned. The swiotlb bounce buffer
> has been masked to be visible to host during boot up.
> 
> rx/tx ring buffer is allocated via vzalloc() and they need to be
> mapped into unencrypted address space(above vTOM) before sharing
> with host and accessing. Add hv_map/unmap_memory() to map/umap rx
> /tx ring buffer.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> ---
> Change since v2:
>        * Add hv_map/unmap_memory() to map/umap rx/tx ring buffer.
> ---
>  arch/x86/hyperv/ivm.c             |  28 ++++++
>  drivers/hv/hv_common.c            |  11 +++
>  drivers/net/hyperv/hyperv_net.h   |   5 ++
>  drivers/net/hyperv/netvsc.c       | 136 +++++++++++++++++++++++++++++-
>  drivers/net/hyperv/netvsc_drv.c   |   1 +
>  drivers/net/hyperv/rndis_filter.c |   2 +
>  include/asm-generic/mshyperv.h    |   2 +
>  include/linux/hyperv.h            |   5 ++
>  8 files changed, 187 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> index 69c7a57f3307..9f78d8f67ea3 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -287,3 +287,31 @@ int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visibl
>  	kfree(pfn_array);
>  	return ret;
>  }
> +
> +/*
> + * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM.
> + */
> +void *hv_map_memory(void *addr, unsigned long size)
> +{
> +	unsigned long *pfns = kcalloc(size / HV_HYP_PAGE_SIZE,

This should be just PAGE_SIZE, as this code is unrelated to communication
with Hyper-V.

> +				      sizeof(unsigned long), GFP_KERNEL);
> +	void *vaddr;
> +	int i;
> +
> +	if (!pfns)
> +		return NULL;
> +
> +	for (i = 0; i < size / PAGE_SIZE; i++)
> +		pfns[i] = virt_to_hvpfn(addr + i * PAGE_SIZE) +

Same here:  Use virt_to_pfn().

> +			(ms_hyperv.shared_gpa_boundary >> PAGE_SHIFT);
> +
> +	vaddr = vmap_pfn(pfns, size / PAGE_SIZE, PAGE_KERNEL_IO);
> +	kfree(pfns);
> +
> +	return vaddr;
> +}
> +
> +void hv_unmap_memory(void *addr)
> +{
> +	vunmap(addr);
> +}
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index 7be173a99f27..3c5cb1f70319 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -295,3 +295,14 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_s
>  	return HV_STATUS_INVALID_PARAMETER;
>  }
>  EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
> +
> +void __weak *hv_map_memory(void *addr, unsigned long size)
> +{
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(hv_map_memory);
> +
> +void __weak hv_unmap_memory(void *addr)
> +{
> +}
> +EXPORT_SYMBOL_GPL(hv_unmap_memory);
> diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
> index 315278a7cf88..cf69da0e296c 100644
> --- a/drivers/net/hyperv/hyperv_net.h
> +++ b/drivers/net/hyperv/hyperv_net.h
> @@ -164,6 +164,7 @@ struct hv_netvsc_packet {
>  	u32 total_bytes;
>  	u32 send_buf_index;
>  	u32 total_data_buflen;
> +	struct hv_dma_range *dma_range;
>  };
> 
>  #define NETVSC_HASH_KEYLEN 40
> @@ -1074,6 +1075,7 @@ struct netvsc_device {
> 
>  	/* Receive buffer allocated by us but manages by NetVSP */
>  	void *recv_buf;
> +	void *recv_original_buf;
>  	u32 recv_buf_size; /* allocated bytes */
>  	struct vmbus_gpadl recv_buf_gpadl_handle;
>  	u32 recv_section_cnt;
> @@ -1082,6 +1084,7 @@ struct netvsc_device {
> 
>  	/* Send buffer allocated by us */
>  	void *send_buf;
> +	void *send_original_buf;
>  	u32 send_buf_size;
>  	struct vmbus_gpadl send_buf_gpadl_handle;
>  	u32 send_section_cnt;
> @@ -1731,4 +1734,6 @@ struct rndis_message {
>  #define RETRY_US_HI	10000
>  #define RETRY_MAX	2000	/* >10 sec */
> 
> +void netvsc_dma_unmap(struct hv_device *hv_dev,
> +		      struct hv_netvsc_packet *packet);
>  #endif /* _HYPERV_NET_H */
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> index 396bc1c204e6..b7ade735a806 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -153,8 +153,21 @@ static void free_netvsc_device(struct rcu_head *head)
>  	int i;
> 
>  	kfree(nvdev->extension);
> -	vfree(nvdev->recv_buf);
> -	vfree(nvdev->send_buf);
> +
> +	if (nvdev->recv_original_buf) {
> +		hv_unmap_memory(nvdev->recv_buf);
> +		vfree(nvdev->recv_original_buf);
> +	} else {
> +		vfree(nvdev->recv_buf);
> +	}
> +
> +	if (nvdev->send_original_buf) {
> +		hv_unmap_memory(nvdev->send_buf);
> +		vfree(nvdev->send_original_buf);
> +	} else {
> +		vfree(nvdev->send_buf);
> +	}
> +
>  	kfree(nvdev->send_section_map);
> 
>  	for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
> @@ -338,6 +351,7 @@ static int netvsc_init_buf(struct hv_device *device,
>  	unsigned int buf_size;
>  	size_t map_words;
>  	int i, ret = 0;
> +	void *vaddr;
> 
>  	/* Get receive buffer area. */
>  	buf_size = device_info->recv_sections * device_info->recv_section_size;
> @@ -373,6 +387,17 @@ static int netvsc_init_buf(struct hv_device *device,
>  		goto cleanup;
>  	}
> 
> +	if (hv_isolation_type_snp()) {
> +		vaddr = hv_map_memory(net_device->recv_buf, buf_size);
> +		if (!vaddr) {
> +			ret = -ENOMEM;
> +			goto cleanup;
> +		}
> +
> +		net_device->recv_original_buf = net_device->recv_buf;
> +		net_device->recv_buf = vaddr;
> +	}
> +
>  	/* Notify the NetVsp of the gpadl handle */
>  	init_packet = &net_device->channel_init_pkt;
>  	memset(init_packet, 0, sizeof(struct nvsp_message));
> @@ -476,6 +501,17 @@ static int netvsc_init_buf(struct hv_device *device,
>  		goto cleanup;
>  	}
> 
> +	if (hv_isolation_type_snp()) {
> +		vaddr = hv_map_memory(net_device->send_buf, buf_size);
> +		if (!vaddr) {
> +			ret = -ENOMEM;
> +			goto cleanup;
> +		}
> +
> +		net_device->send_original_buf = net_device->send_buf;
> +		net_device->send_buf = vaddr;
> +	}
> +
>  	/* Notify the NetVsp of the gpadl handle */
>  	init_packet = &net_device->channel_init_pkt;
>  	memset(init_packet, 0, sizeof(struct nvsp_message));
> @@ -766,7 +802,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
> 
>  	/* Notify the layer above us */
>  	if (likely(skb)) {
> -		const struct hv_netvsc_packet *packet
> +		struct hv_netvsc_packet *packet
>  			= (struct hv_netvsc_packet *)skb->cb;
>  		u32 send_index = packet->send_buf_index;
>  		struct netvsc_stats *tx_stats;
> @@ -782,6 +818,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
>  		tx_stats->bytes += packet->total_bytes;
>  		u64_stats_update_end(&tx_stats->syncp);
> 
> +		netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
>  		napi_consume_skb(skb, budget);
>  	}
> 
> @@ -946,6 +983,88 @@ static void netvsc_copy_to_send_buf(struct netvsc_device *net_device,
>  		memset(dest, 0, padding);
>  }
> 
> +void netvsc_dma_unmap(struct hv_device *hv_dev,
> +		      struct hv_netvsc_packet *packet)
> +{
> +	u32 page_count = packet->cp_partial ?
> +		packet->page_buf_cnt - packet->rmsg_pgcnt :
> +		packet->page_buf_cnt;
> +	int i;
> +
> +	if (!hv_is_isolation_supported())
> +		return;
> +
> +	if (!packet->dma_range)
> +		return;
> +
> +	for (i = 0; i < page_count; i++)
> +		dma_unmap_single(&hv_dev->device, packet->dma_range[i].dma,
> +				 packet->dma_range[i].mapping_size,
> +				 DMA_TO_DEVICE);
> +
> +	kfree(packet->dma_range);
> +}
> +
> +/* netvsc_dma_map - Map swiotlb bounce buffer with data page of
> + * packet sent by vmbus_sendpacket_pagebuffer() in the Isolation
> + * VM.
> + *
> + * In isolation VM, netvsc send buffer has been marked visible to
> + * host and so the data copied to send buffer doesn't need to use
> + * bounce buffer. The data pages handled by vmbus_sendpacket_pagebuffer()
> + * may not be copied to send buffer and so these pages need to be
> + * mapped with swiotlb bounce buffer. netvsc_dma_map() is to do
> + * that. The pfns in the struct hv_page_buffer need to be converted
> + * to bounce buffer's pfn. The loop here is necessary because the
> + * entries in the page buffer array are not necessarily full
> + * pages of data.  Each entry in the array has a separate offset and
> + * len that may be non-zero, even for entries in the middle of the
> + * array.  And the entries are not physically contiguous.  So each
> + * entry must be individually mapped rather than as a contiguous unit.
> + * So not use dma_map_sg() here.
> + */
> +int netvsc_dma_map(struct hv_device *hv_dev,
> +		   struct hv_netvsc_packet *packet,
> +		   struct hv_page_buffer *pb)
> +{
> +	u32 page_count =  packet->cp_partial ?
> +		packet->page_buf_cnt - packet->rmsg_pgcnt :
> +		packet->page_buf_cnt;
> +	dma_addr_t dma;
> +	int i;
> +
> +	if (!hv_is_isolation_supported())
> +		return 0;
> +
> +	packet->dma_range = kcalloc(page_count,
> +				    sizeof(*packet->dma_range),
> +				    GFP_KERNEL);
> +	if (!packet->dma_range)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < page_count; i++) {
> +		char *src = phys_to_virt((pb[i].pfn << HV_HYP_PAGE_SHIFT)
> +					 + pb[i].offset);
> +		u32 len = pb[i].len;
> +
> +		dma = dma_map_single(&hv_dev->device, src, len,
> +				     DMA_TO_DEVICE);
> +		if (dma_mapping_error(&hv_dev->device, dma)) {
> +			kfree(packet->dma_range);
> +			return -ENOMEM;
> +		}
> +
> +		/* pb[].offset and pb[].len are not changed during dma mapping
> +		 * and so not reassign.
> +		 */
> +		packet->dma_range[i].dma = dma;
> +		packet->dma_range[i].mapping_size = len;
> +		pb[i].pfn = dma >> HV_HYP_PAGE_SHIFT;
> +	}
> +
> +	return 0;
> +}
> +
>  static inline int netvsc_send_pkt(
>  	struct hv_device *device,
>  	struct hv_netvsc_packet *packet,
> @@ -986,14 +1105,24 @@ static inline int netvsc_send_pkt(
> 
>  	trace_nvsp_send_pkt(ndev, out_channel, rpkt);
> 
> +	packet->dma_range = NULL;
>  	if (packet->page_buf_cnt) {
>  		if (packet->cp_partial)
>  			pb += packet->rmsg_pgcnt;
> 
> +		ret = netvsc_dma_map(ndev_ctx->device_ctx, packet, pb);
> +		if (ret) {
> +			ret = -EAGAIN;
> +			goto exit;
> +		}
> +
>  		ret = vmbus_sendpacket_pagebuffer(out_channel,
>  						  pb, packet->page_buf_cnt,
>  						  &nvmsg, sizeof(nvmsg),
>  						  req_id);
> +
> +		if (ret)
> +			netvsc_dma_unmap(ndev_ctx->device_ctx, packet);
>  	} else {
>  		ret = vmbus_sendpacket(out_channel,
>  				       &nvmsg, sizeof(nvmsg),
> @@ -1001,6 +1130,7 @@ static inline int netvsc_send_pkt(
>  				       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
>  	}
> 
> +exit:
>  	if (ret == 0) {
>  		atomic_inc_return(&nvchan->queue_sends);
> 
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 7e66ae1d2a59..17958533bf30 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -2512,6 +2512,7 @@ static int netvsc_probe(struct hv_device *dev,
>  	net->netdev_ops = &device_ops;
>  	net->ethtool_ops = &ethtool_ops;
>  	SET_NETDEV_DEV(net, &dev->device);
> +	dma_set_min_align_mask(&dev->device, HV_HYP_PAGE_SIZE - 1);
> 
>  	/* We always need headroom for rndis header */
>  	net->needed_headroom = RNDIS_AND_PPI_SIZE;
> diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
> index f6c9c2a670f9..448fcc325ed7 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -361,6 +361,8 @@ static void rndis_filter_receive_response(struct net_device *ndev,
>  			}
>  		}
> 
> +		netvsc_dma_unmap(((struct net_device_context *)
> +			netdev_priv(ndev))->device_ctx, &request->pkt);
>  		complete(&request->wait_event);
>  	} else {
>  		netdev_err(ndev,
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index 3e2248ac328e..94e73ba129c5 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -269,6 +269,8 @@ bool hv_isolation_type_snp(void);
>  u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);
>  void hyperv_cleanup(void);
>  bool hv_query_ext_cap(u64 cap_query);
> +void *hv_map_memory(void *addr, unsigned long size);
> +void hv_unmap_memory(void *addr);
>  #else /* CONFIG_HYPERV */
>  static inline bool hv_is_hyperv_initialized(void) { return false; }
>  static inline bool hv_is_hibernation_supported(void) { return false; }
> diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
> index 74f5e92f91a0..b53cfc4163af 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -1584,6 +1584,11 @@ struct hyperv_service_callback {
>  	void (*callback)(void *context);
>  };
> 
> +struct hv_dma_range {
> +	dma_addr_t dma;
> +	u32 mapping_size;
> +};
> +
>  #define MAX_SRV_VER	0x7ffffff
>  extern bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf, u32 buflen,
>  				const int *fw_version, int fw_vercnt,
> --
> 2.25.1

Re: [PATCH V3 5/5] hv_netvsc: Add Isolation VM support for netvsc driver

[Tianyu Lan]

On 12/4/2021 2:59 AM, Michael Kelley (LINUX) wrote:
>> +
>> +/*
>> + * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM.
>> + */
>> +void *hv_map_memory(void *addr, unsigned long size)
>> +{
>> +	unsigned long *pfns = kcalloc(size / HV_HYP_PAGE_SIZE,
> This should be just PAGE_SIZE, as this code is unrelated to communication
> with Hyper-V.
>

Yes, agree. Will update.