[PATCH V7 0/5] x86/Hyper-V: Add Hyper-V Isolation VM support(Second part)

[PATCH V7 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
drivers in Isolation VM.

Change since v6:
        * Fix compile error in hv_init.c and mshyperv.c when swiotlb
	  is not enabled.
	* Change the order in the cc_platform_has() and check sev first. 

Change sicne v5:
        * Modify "Swiotlb" to "swiotlb" in commit log.
	* Remove CONFIG_HYPERV check in the hyperv_cc_platform_has()

Change since v4:
	* Remove Hyper-V IOMMU IOMMU_INIT_FINISH related functions
	  and set SWIOTLB_FORCE and swiotlb_unencrypted_base in the
	  ms_hyperv_init_platform(). Call swiotlb_update_mem_attributes()
	  in the hyperv_init().

Change since v3:
	* Fix boot up failure on the host with mem_encrypt=on.
	  Move calloing of set_memory_decrypted() back from
	  swiotlb_init_io_tlb_mem to swiotlb_late_init_with_tbl()
	  and rmem_swiotlb_device_init().
	* Change code style of checking GUEST_MEM attribute in the
	  hyperv_cc_platform_has().
	* Add comment in pci-swiotlb-xen.c to explain why add
	  dependency between hyperv_swiotlb_detect() and pci_
	  xen_swiotlb_detect().
	* Return directly when fails to allocate Hyper-V swiotlb
	  buffer in the hyperv_iommu_swiotlb_init().

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()
  hyper-v: Enable swiotlb bounce buffer for Isolation VM
  scsi: storvsc: Add Isolation VM support for storvsc driver
  net: netvsc: Add Isolation VM support for netvsc driver

 arch/x86/hyperv/hv_init.c         |  12 +++
 arch/x86/hyperv/ivm.c             |  28 ++++++
 arch/x86/kernel/cc_platform.c     |   8 ++
 arch/x86/kernel/cpu/mshyperv.c    |  15 +++-
 drivers/hv/hv_common.c            |  11 +++
 drivers/hv/vmbus_drv.c            |   4 +
 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            |   6 ++
 include/linux/swiotlb.h           |   6 ++
 kernel/dma/swiotlb.c              |  43 +++++++++-
 15 files changed, 294 insertions(+), 22 deletions(-)

-- 
2.25.1

[PATCH V7 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.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v3:
	* Fix boot up failure on the host with mem_encrypt=on.
	  Move calloing of set_memory_decrypted() back from
	  swiotlb_init_io_tlb_mem to swiotlb_late_init_with_tbl()
	  and rmem_swiotlb_device_init().

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    | 43 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 47 insertions(+), 2 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..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)
-- 
2.25.1

[PATCH V7 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 for confidential computing support and
guest memory is encrypted in it. Places checking cc_platform_has()
with GUEST_MEM_ENCRYPT attr should return "True" in Isolation vm. e.g,
swiotlb bounce buffer size needs to adjust according to memory size
in the sev_setup_arch(). Add GUEST_MEM_ENCRYPT check for Hyper-V Isolation
VM.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v6:
	* Change the order in the cc_platform_has() and check sev first.

Change since v3:
	* Change code style of checking GUEST_MEM attribute in the
	  hyperv_cc_platform_has().
---
 arch/x86/kernel/cc_platform.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
index 03bb2f343ddb..6cb3a675e686 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)
@@ -58,12 +59,19 @@ static bool amd_cc_platform_has(enum cc_attr attr)
 #endif
 }
 
+static bool hyperv_cc_platform_has(enum cc_attr attr)
+{
+	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;
+}
 
 bool cc_platform_has(enum cc_attr attr)
 {
 	if (sme_me_mask)
 		return amd_cc_platform_has(attr);
 
+	if (hv_is_isolation_supported())
+		return hyperv_cc_platform_has(attr);
+
 	return false;
 }
 EXPORT_SYMBOL_GPL(cc_platform_has);
-- 
2.25.1

[PATCH V7 3/5] hyper-v: 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.

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
(e.g ms_hyperv_init_platform()) and so call swiotlb_update_mem_
attributes() in the hyperv_init().

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v6:
        * Fix compile error when swiotlb is not enabled.

Change since v4:
	* Remove Hyper-V IOMMU IOMMU_INIT_FINISH related functions
	  and set SWIOTLB_FORCE and swiotlb_unencrypted_base in the
	  ms_hyperv_init_platform(). Call swiotlb_update_mem_attributes()
	  in the hyperv_init().

Change since v3:
	* Add comment in pci-swiotlb-xen.c to explain why add
	  dependency between hyperv_swiotlb_detect() and pci_
	  xen_swiotlb_detect().
	* Return directly when fails to allocate Hyper-V swiotlb
	  buffer in the hyperv_iommu_swiotlb_init().
---
 arch/x86/hyperv/hv_init.c      | 12 ++++++++++++
 arch/x86/kernel/cpu/mshyperv.c | 15 ++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 24f4a06ac46a..749906a8e068 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -28,6 +28,7 @@
 #include <linux/syscore_ops.h>
 #include <clocksource/hyperv_timer.h>
 #include <linux/highmem.h>
+#include <linux/swiotlb.h>
 
 int hyperv_init_cpuhp;
 u64 hv_current_partition_id = ~0ull;
@@ -502,6 +503,17 @@ void __init hyperv_init(void)
 
 	/* Query the VMs extended capability once, so that it can be cached. */
 	hv_query_ext_cap(0);
+
+#ifdef CONFIG_SWIOTLB
+	/*
+	 * 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.
+	 */
+	if (hv_is_isolation_supported())
+		swiotlb_update_mem_attributes();
+#endif
+
 	return;
 
 clean_guest_os_id:
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 4794b716ec79..e3a240c5e4f5 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -18,6 +18,7 @@
 #include <linux/kexec.h>
 #include <linux/i8253.h>
 #include <linux/random.h>
+#include <linux/swiotlb.h>
 #include <asm/processor.h>
 #include <asm/hypervisor.h>
 #include <asm/hyperv-tlfs.h>
@@ -319,8 +320,20 @@ static void __init ms_hyperv_init_platform(void)
 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
 
-		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
+		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
 			static_branch_enable(&isolation_type_snp);
+#ifdef CONFIG_SWIOTLB
+			swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary;
+#endif
+		}
+
+#ifdef CONFIG_SWIOTLB
+		/*
+		 * Enable swiotlb force mode in Isolation VM to
+		 * use swiotlb bounce buffer for dma transaction.
+		 */
+		swiotlb_force = SWIOTLB_FORCE;
+#endif
 	}
 
 	if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
-- 
2.25.1

[PATCH V7 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     |  4 ++++
 drivers/scsi/storvsc_drv.c | 37 +++++++++++++++++++++----------------
 include/linux/hyperv.h     |  1 +
 3 files changed, 26 insertions(+), 16 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 392c1ac4f819..ae6ec503399a 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 +2120,8 @@ 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 b823311eac79..650a0574b746 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 V7 5/5] net: 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 address 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 v3:
       * Replace HV_HYP_PAGE_SIZE with PAGE_SIZE and virt_to_hvpfn()
         with vmalloc_to_pfn() in the hv_map_memory()

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..2b994117581e 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 / 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] = vmalloc_to_pfn(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 650a0574b746..f565a8938836 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 V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM

[Dave Hansen]

On 12/12/21 11:14 PM, Tianyu Lan wrote:
> 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.

This seems to be independently reintroducing some of the SEV
infrastructure.  Is it really OK that this doesn't interact at all with
any existing SEV code?

For instance, do we need a new 'swiotlb_unencrypted_base', or should
this just be using sme_me_mask somehow?

RE: [PATCH V7 5/5] net: netvsc: Add Isolation VM support for netvsc driver

[Haiyang Zhang]

> -----Original Message-----
> From: Tianyu Lan <ltykernel@gmail.com>
> Sent: Monday, December 13, 2021 2:14 AM
> To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.com>; Stephen
> Hemminger <sthemmin@microsoft.com>; wei.liu@kernel.org; Dexuan Cui <decui@microsoft.com>;
> tglx@linutronix.de; mingo@redhat.com; bp@alien8.de; dave.hansen@linux.intel.com;
> x86@kernel.org; hpa@zytor.com; davem@davemloft.net; kuba@kernel.org; jejb@linux.ibm.com;
> martin.petersen@oracle.com; arnd@arndb.de; hch@infradead.org; m.szyprowski@samsung.com;
> robin.murphy@arm.com; thomas.lendacky@amd.com; Tianyu Lan <Tianyu.Lan@microsoft.com>;
> Michael Kelley (LINUX) <mikelley@microsoft.com>
> Cc: 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 <vkuznets@redhat.com>; brijesh.singh@amd.com;
> konrad.wilk@oracle.com; hch@lst.de; joro@8bytes.org; parri.andrea@gmail.com;
> dave.hansen@intel.com
> Subject: [PATCH V7 5/5] net: netvsc: Add Isolation VM support for netvsc driver
> 
> 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 address 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 v3:
>        * Replace HV_HYP_PAGE_SIZE with PAGE_SIZE and virt_to_hvpfn()
>          with vmalloc_to_pfn() in the hv_map_memory()
> 
> 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(-)
> 

Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>

Re: [PATCH V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM

[Tianyu Lan]

On 12/14/2021 12:45 AM, Dave Hansen wrote:
> On 12/12/21 11:14 PM, Tianyu Lan wrote:
>> 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.
> 
> This seems to be independently reintroducing some of the SEV
> infrastructure.  Is it really OK that this doesn't interact at all with
> any existing SEV code?
> 
> For instance, do we need a new 'swiotlb_unencrypted_base', or should
> this just be using sme_me_mask somehow?

Hi Dave:
        Thanks for your review. Hyper-V provides a para-virtualized
confidential computing solution based on the AMD SEV function and not
expose sev&sme capabilities to guest. So sme_me_mask is unset in the
Hyper-V Isolation VM. swiotlb_unencrypted_base is more general solution
to handle such case of different address space for encrypted and
decrypted memory and other platform also may reuse it.

Re: [PATCH V7 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Wei Liu]

On Mon, Dec 13, 2021 at 02:14:03AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> Hyper-V provides Isolation VM for confidential computing support and
> guest memory is encrypted in it. Places checking cc_platform_has()
> with GUEST_MEM_ENCRYPT attr should return "True" in Isolation vm. e.g,
> swiotlb bounce buffer size needs to adjust according to memory size
> in the sev_setup_arch(). Add GUEST_MEM_ENCRYPT check for Hyper-V Isolation
> VM.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>

x86 maintainers, any comment on this patch?

> ---
> Change since v6:
> 	* Change the order in the cc_platform_has() and check sev first.
> 
> Change since v3:
> 	* Change code style of checking GUEST_MEM attribute in the
> 	  hyperv_cc_platform_has().
> ---
>  arch/x86/kernel/cc_platform.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
> index 03bb2f343ddb..6cb3a675e686 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)
> @@ -58,12 +59,19 @@ static bool amd_cc_platform_has(enum cc_attr attr)
>  #endif
>  }
>  
> +static bool hyperv_cc_platform_has(enum cc_attr attr)
> +{
> +	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;
> +}
>  
>  bool cc_platform_has(enum cc_attr attr)
>  {
>  	if (sme_me_mask)
>  		return amd_cc_platform_has(attr);
>  
> +	if (hv_is_isolation_supported())
> +		return hyperv_cc_platform_has(attr);
> +
>  	return false;
>  }
>  EXPORT_SYMBOL_GPL(cc_platform_has);
> -- 
> 2.25.1
> 

Re: [PATCH V7 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Borislav Petkov]

On Mon, Dec 13, 2021 at 02:14:03AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> Hyper-V provides Isolation VM for confidential computing support and
> guest memory is encrypted in it. Places checking cc_platform_has()
> with GUEST_MEM_ENCRYPT attr should return "True" in Isolation vm. e.g,

Stick to a single spelling variant: "VM".

> swiotlb bounce buffer size needs to adjust according to memory size
> in the sev_setup_arch().

So basically you wanna simply say here:

"Hyper-V Isolation VMs need to adjust the SWIOTLB size just like SEV
guests. Add a hyperv_cc_platform_has() variant which enables that."

?

With that addressed you can have my

Acked-by: Borislav Petkov <bp@suse.de>

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH V7 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Wei Liu]

On Tue, Dec 14, 2021 at 05:05:01PM +0100, Borislav Petkov wrote:
> On Mon, Dec 13, 2021 at 02:14:03AM -0500, Tianyu Lan wrote:
> > From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> > 
> > Hyper-V provides Isolation VM for confidential computing support and
> > guest memory is encrypted in it. Places checking cc_platform_has()
> > with GUEST_MEM_ENCRYPT attr should return "True" in Isolation vm. e.g,
> 
> Stick to a single spelling variant: "VM".
> 
> > swiotlb bounce buffer size needs to adjust according to memory size
> > in the sev_setup_arch().
> 
> So basically you wanna simply say here:
> 
> "Hyper-V Isolation VMs need to adjust the SWIOTLB size just like SEV
> guests. Add a hyperv_cc_platform_has() variant which enables that."
> 
> ?
> 
> With that addressed you can have my
> 
> Acked-by: Borislav Petkov <bp@suse.de>

Thanks. I can address your comments when I pick up this series.

Wei.

> 
> Thx.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

RE: [PATCH V7 0/5] x86/Hyper-V: Add Hyper-V Isolation VM support(Second part)

[Michael Kelley (LINUX)]

From: Tianyu Lan <ltykernel@gmail.com> Sent: Sunday, December 12, 2021 11:14 PM
> 
> 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
> drivers in Isolation VM.
> 
> Change since v6:
>         * Fix compile error in hv_init.c and mshyperv.c when swiotlb
> 	  is not enabled.
> 	* Change the order in the cc_platform_has() and check sev first.
> 
> Change sicne v5:
>         * Modify "Swiotlb" to "swiotlb" in commit log.
> 	* Remove CONFIG_HYPERV check in the hyperv_cc_platform_has()
> 
> Change since v4:
> 	* Remove Hyper-V IOMMU IOMMU_INIT_FINISH related functions
> 	  and set SWIOTLB_FORCE and swiotlb_unencrypted_base in the
> 	  ms_hyperv_init_platform(). Call swiotlb_update_mem_attributes()
> 	  in the hyperv_init().
> 
> Change since v3:
> 	* Fix boot up failure on the host with mem_encrypt=on.
> 	  Move calloing of set_memory_decrypted() back from
> 	  swiotlb_init_io_tlb_mem to swiotlb_late_init_with_tbl()
> 	  and rmem_swiotlb_device_init().
> 	* Change code style of checking GUEST_MEM attribute in the
> 	  hyperv_cc_platform_has().
> 	* Add comment in pci-swiotlb-xen.c to explain why add
> 	  dependency between hyperv_swiotlb_detect() and pci_
> 	  xen_swiotlb_detect().
> 	* Return directly when fails to allocate Hyper-V swiotlb
> 	  buffer in the hyperv_iommu_swiotlb_init().
> 
> 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()
>   hyper-v: Enable swiotlb bounce buffer for Isolation VM
>   scsi: storvsc: Add Isolation VM support for storvsc driver
>   net: netvsc: Add Isolation VM support for netvsc driver
> 
>  arch/x86/hyperv/hv_init.c         |  12 +++
>  arch/x86/hyperv/ivm.c             |  28 ++++++
>  arch/x86/kernel/cc_platform.c     |   8 ++
>  arch/x86/kernel/cpu/mshyperv.c    |  15 +++-
>  drivers/hv/hv_common.c            |  11 +++
>  drivers/hv/vmbus_drv.c            |   4 +
>  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            |   6 ++
>  include/linux/swiotlb.h           |   6 ++
>  kernel/dma/swiotlb.c              |  43 +++++++++-
>  15 files changed, 294 insertions(+), 22 deletions(-)
> 
> --
> 2.25.1

For the entire series,

Reviewed-by: Michael Kelley <mikelley@microsoft.com>

Re: [PATCH V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM

[Dave Hansen]

On 12/13/21 8:36 PM, Tianyu Lan wrote:
> On 12/14/2021 12:45 AM, Dave Hansen wrote:
>> On 12/12/21 11:14 PM, Tianyu Lan wrote:
>>> 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.
>>
>> This seems to be independently reintroducing some of the SEV
>> infrastructure.  Is it really OK that this doesn't interact at all with
>> any existing SEV code?
>>
>> For instance, do we need a new 'swiotlb_unencrypted_base', or should
>> this just be using sme_me_mask somehow?
> 
>        Thanks for your review. Hyper-V provides a para-virtualized
> confidential computing solution based on the AMD SEV function and not
> expose sev&sme capabilities to guest. So sme_me_mask is unset in the
> Hyper-V Isolation VM. swiotlb_unencrypted_base is more general solution
> to handle such case of different address space for encrypted and
> decrypted memory and other platform also may reuse it.

I don't really understand how this can be more general any *not* get
utilized by the existing SEV support.

Re: [PATCH V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM

[Tom Lendacky]

On 12/14/21 12:40 PM, Dave Hansen wrote:
> On 12/13/21 8:36 PM, Tianyu Lan wrote:
>> On 12/14/2021 12:45 AM, Dave Hansen wrote:
>>> On 12/12/21 11:14 PM, Tianyu Lan wrote:
>>>> 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.
>>>
>>> This seems to be independently reintroducing some of the SEV
>>> infrastructure.  Is it really OK that this doesn't interact at all with
>>> any existing SEV code?
>>>
>>> For instance, do we need a new 'swiotlb_unencrypted_base', or should
>>> this just be using sme_me_mask somehow?
>>
>>         Thanks for your review. Hyper-V provides a para-virtualized
>> confidential computing solution based on the AMD SEV function and not
>> expose sev&sme capabilities to guest. So sme_me_mask is unset in the
>> Hyper-V Isolation VM. swiotlb_unencrypted_base is more general solution
>> to handle such case of different address space for encrypted and
>> decrypted memory and other platform also may reuse it.
> 
> I don't really understand how this can be more general any *not* get
> utilized by the existing SEV support.

The Virtual Top-of-Memory (VTOM) support is an SEV-SNP feature that is 
meant to be used with a (relatively) un-enlightened guest. The idea is 
that the C-bit in the guest page tables must be 0 for all accesses. It is 
only the physical address relative to VTOM that determines if the access 
is encrypted or not. So setting sme_me_mask will actually cause issues 
when running with this feature. Since all DMA for an SEV-SNP guest must 
still be to shared (unencrypted) memory, some enlightenment is needed. In 
this case, memory mapped above VTOM will provide that via the SWIOTLB 
update. For SEV-SNP guests running with VTOM, they are likely to also be 
running with the Reflect #VC feature, allowing a "paravisor" to handle any 
#VCs generated by the guest.

See sections 15.36.8 "Virtual Top-of-Memory" and 15.36.9 "Reflect #VC" in 
volume 2 of the AMD APM [1].

I'm not sure if that will answer your question or generate more :)

Thanks,
Tom

[1] https://www.amd.com/system/files/TechDocs/24593.pdf

> 

Re: [PATCH V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM

[Dave Hansen]

On 12/14/21 2:23 PM, Tom Lendacky wrote:
>> I don't really understand how this can be more general any *not* get
>> utilized by the existing SEV support.
> 
> The Virtual Top-of-Memory (VTOM) support is an SEV-SNP feature that is
> meant to be used with a (relatively) un-enlightened guest. The idea is
> that the C-bit in the guest page tables must be 0 for all accesses. It
> is only the physical address relative to VTOM that determines if the
> access is encrypted or not. So setting sme_me_mask will actually cause
> issues when running with this feature. Since all DMA for an SEV-SNP
> guest must still be to shared (unencrypted) memory, some enlightenment
> is needed. In this case, memory mapped above VTOM will provide that via
> the SWIOTLB update. For SEV-SNP guests running with VTOM, they are
> likely to also be running with the Reflect #VC feature, allowing a
> "paravisor" to handle any #VCs generated by the guest.
> 
> See sections 15.36.8 "Virtual Top-of-Memory" and 15.36.9 "Reflect #VC"
> in volume 2 of the AMD APM [1].

Thanks, Tom, that's pretty much what I was looking for.

The C-bit normally comes from the page tables.  But, the hardware also
provides an alternative way to effectively get C-bit behavior without
actually setting the bit in the page tables: Virtual Top-of-Memory
(VTOM).  Right?

It sounds like Hyper-V has chosen to use VTOM instead of requiring the
guest to do the C-bit in its page tables.

But, the thing that confuses me is when you said: "it (VTOM) is meant to
be used with a (relatively) un-enlightened guest".  We don't have an
unenlightened guest here.  We have Linux, which is quite enlightened.

Is VTOM being used because there's something that completely rules out
using the C-bit in the page tables?  What's that "something"?

Re: [PATCH V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM

[Tianyu Lan]

On 12/15/2021 6:40 AM, Dave Hansen wrote:
> On 12/14/21 2:23 PM, Tom Lendacky wrote:
>>> I don't really understand how this can be more general any *not* get
>>> utilized by the existing SEV support.
>>
>> The Virtual Top-of-Memory (VTOM) support is an SEV-SNP feature that is
>> meant to be used with a (relatively) un-enlightened guest. The idea is
>> that the C-bit in the guest page tables must be 0 for all accesses. It
>> is only the physical address relative to VTOM that determines if the
>> access is encrypted or not. So setting sme_me_mask will actually cause
>> issues when running with this feature. Since all DMA for an SEV-SNP
>> guest must still be to shared (unencrypted) memory, some enlightenment
>> is needed. In this case, memory mapped above VTOM will provide that via
>> the SWIOTLB update. For SEV-SNP guests running with VTOM, they are
>> likely to also be running with the Reflect #VC feature, allowing a
>> "paravisor" to handle any #VCs generated by the guest.
>>
>> See sections 15.36.8 "Virtual Top-of-Memory" and 15.36.9 "Reflect #VC"
>> in volume 2 of the AMD APM [1].
> 
> Thanks, Tom, that's pretty much what I was looking for.
> 
> The C-bit normally comes from the page tables.  But, the hardware also
> provides an alternative way to effectively get C-bit behavior without
> actually setting the bit in the page tables: Virtual Top-of-Memory
> (VTOM).  Right?
> 
> It sounds like Hyper-V has chosen to use VTOM instead of requiring the
> guest to do the C-bit in its page tables.
> 
> But, the thing that confuses me is when you said: "it (VTOM) is meant to
> be used with a (relatively) un-enlightened guest".  We don't have an
> unenlightened guest here.  We have Linux, which is quite enlightened.
>
>> Is VTOM being used because there's something that completely rules out
>> using the C-bit in the page tables?  What's that "something"?


For "un-enlightened" guest, there is an another system running insider
the VM to emulate some functions(tsc, timer, interrupt and so on) and
this helps not to modify OS(Linux/Windows) a lot. In Hyper-V Isolation
VM, we called the new system as HCL/paravisor. HCL runs in the VMPL0 and 
Linux runs in VMPL2. This is similar with nested virtualization. HCL
plays similar role as L1 hypervisor to emulate some general functions
(e.g, rdmsr/wrmsr accessing and interrupt injection) which needs to be
enlightened in the enlightened guest. Linux kernel needs to handle
#vc/#ve exception directly in the enlightened guest. HCL handles such
exception in un-enlightened guest and emulate interrupt injection which
helps not to modify OS core part code. Using vTOM also is same purpose.
Hyper-V uses vTOM avoid changing page table related code in OS(include
Windows and Linux)and just needs to map memory into decrypted address
space above vTOM in the driver code.

Linux has generic swiotlb bounce buffer implementation and so introduce
swiotlb_unencrypted_base here to set shared memory boundary or vTOM.
Hyper-V Isolation VM is un-enlightened guest. Hyper-V doesn't expose 
sev/sme capability to guest and so SEV code actually doesn't work.
So we also can't interact current existing SEV code and these code is
for enlightened guest support without HCL/paravisor. If other platforms
or SEV want to use similar vTOM feature, swiotlb_unencrypted_base can
be reused. So swiotlb_unencrypted_base is a general solution for all
platforms besides SEV and Hyper-V.

RE: [PATCH V7 4/5] scsi: storvsc: Add Isolation VM support for storvsc driver

[Long Li]

> From: Tianyu Lan <ltykernel@gmail.com>
> Sent: Sunday, December 12, 2021 11:14 PM
> To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> wei.liu@kernel.org; Dexuan Cui <decui@microsoft.com>; tglx@linutronix.de;
> mingo@redhat.com; bp@alien8.de; dave.hansen@linux.intel.com;
> x86@kernel.org; hpa@zytor.com; davem@davemloft.net; kuba@kernel.org;
> jejb@linux.ibm.com; martin.petersen@oracle.com; arnd@arndb.de;
> hch@infradead.org; m.szyprowski@samsung.com; robin.murphy@arm.com;
> thomas.lendacky@amd.com; Tianyu Lan <Tianyu.Lan@microsoft.com>; Michael
> Kelley (LINUX) <mikelley@microsoft.com>
> Cc: 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
> <vkuznets@redhat.com>; brijesh.singh@amd.com; konrad.wilk@oracle.com;
> hch@lst.de; joro@8bytes.org; parri.andrea@gmail.com;
> dave.hansen@intel.com
> Subject: [PATCH V7 4/5] scsi: storvsc: Add Isolation VM support for storvsc driver
> 
> 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>

Reviewed-by: Long Li <longli@microsoft.com>

> ---
>  drivers/hv/vmbus_drv.c     |  4 ++++
>  drivers/scsi/storvsc_drv.c | 37 +++++++++++++++++++++----------------
>  include/linux/hyperv.h     |  1 +
>  3 files changed, 26 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index
> 392c1ac4f819..ae6ec503399a 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 +2120,8 @@ 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
> b823311eac79..650a0574b746 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

Re: [PATCH V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM

[Wei Liu]

On Wed, Dec 15, 2021 at 01:00:38PM +0800, Tianyu Lan wrote:
> 
> 
> On 12/15/2021 6:40 AM, Dave Hansen wrote:
> > On 12/14/21 2:23 PM, Tom Lendacky wrote:
> > > > I don't really understand how this can be more general any *not* get
> > > > utilized by the existing SEV support.
> > > 
> > > The Virtual Top-of-Memory (VTOM) support is an SEV-SNP feature that is
> > > meant to be used with a (relatively) un-enlightened guest. The idea is
> > > that the C-bit in the guest page tables must be 0 for all accesses. It
> > > is only the physical address relative to VTOM that determines if the
> > > access is encrypted or not. So setting sme_me_mask will actually cause
> > > issues when running with this feature. Since all DMA for an SEV-SNP
> > > guest must still be to shared (unencrypted) memory, some enlightenment
> > > is needed. In this case, memory mapped above VTOM will provide that via
> > > the SWIOTLB update. For SEV-SNP guests running with VTOM, they are
> > > likely to also be running with the Reflect #VC feature, allowing a
> > > "paravisor" to handle any #VCs generated by the guest.
> > > 
> > > See sections 15.36.8 "Virtual Top-of-Memory" and 15.36.9 "Reflect #VC"
> > > in volume 2 of the AMD APM [1].
> > 
> > Thanks, Tom, that's pretty much what I was looking for.
> > 
> > The C-bit normally comes from the page tables.  But, the hardware also
> > provides an alternative way to effectively get C-bit behavior without
> > actually setting the bit in the page tables: Virtual Top-of-Memory
> > (VTOM).  Right?
> > 
> > It sounds like Hyper-V has chosen to use VTOM instead of requiring the
> > guest to do the C-bit in its page tables.
> > 
> > But, the thing that confuses me is when you said: "it (VTOM) is meant to
> > be used with a (relatively) un-enlightened guest".  We don't have an
> > unenlightened guest here.  We have Linux, which is quite enlightened.
> > 
> > > Is VTOM being used because there's something that completely rules out
> > > using the C-bit in the page tables?  What's that "something"?
> 
> 
> For "un-enlightened" guest, there is an another system running insider
> the VM to emulate some functions(tsc, timer, interrupt and so on) and
> this helps not to modify OS(Linux/Windows) a lot. In Hyper-V Isolation
> VM, we called the new system as HCL/paravisor. HCL runs in the VMPL0 and
> Linux runs in VMPL2. This is similar with nested virtualization. HCL
> plays similar role as L1 hypervisor to emulate some general functions
> (e.g, rdmsr/wrmsr accessing and interrupt injection) which needs to be
> enlightened in the enlightened guest. Linux kernel needs to handle
> #vc/#ve exception directly in the enlightened guest. HCL handles such
> exception in un-enlightened guest and emulate interrupt injection which
> helps not to modify OS core part code. Using vTOM also is same purpose.
> Hyper-V uses vTOM avoid changing page table related code in OS(include
> Windows and Linux)and just needs to map memory into decrypted address
> space above vTOM in the driver code.
> 
> Linux has generic swiotlb bounce buffer implementation and so introduce
> swiotlb_unencrypted_base here to set shared memory boundary or vTOM.
> Hyper-V Isolation VM is un-enlightened guest. Hyper-V doesn't expose sev/sme
> capability to guest and so SEV code actually doesn't work.
> So we also can't interact current existing SEV code and these code is
> for enlightened guest support without HCL/paravisor. If other platforms
> or SEV want to use similar vTOM feature, swiotlb_unencrypted_base can
> be reused. So swiotlb_unencrypted_base is a general solution for all
> platforms besides SEV and Hyper-V.
> 

Thanks for the detailed explanation.

Dave, are you happy with this?

The code looks pretty solid to my untrained eyes. And the series has
collected necessary acks from stakeholders. If I don't hear objection by
EOD Friday I will apply this series to hyperv-next.

Wei.

Re: [PATCH V7 0/5] x86/Hyper-V: Add Hyper-V Isolation VM support(Second part)

[Wei Liu]

On Mon, Dec 13, 2021 at 02:14:01AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
[...]
> 
> 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()
>   hyper-v: Enable swiotlb bounce buffer for Isolation VM
>   scsi: storvsc: Add Isolation VM support for storvsc driver
>   net: netvsc: Add Isolation VM support for netvsc driver
> 

Applied to hyperv-next. Thanks.

Wei.

Re: [PATCH V7 4/5] scsi: storvsc: Add Isolation VM support for storvsc driver

[Jakub Kicinski]

On Mon, 13 Dec 2021 02:14:05 -0500 Tianyu Lan wrote:
> @@ -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);

This breaks the x86 clang allmodconfig build as I presume those
involved know by now:

../drivers/hv/vmbus_drv.c:2082:29: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
                            ^~~~~~~~~~~~~~~~
../include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
                                                     ^ ~~~
1 error generated.


Is there any ETA on getting the fix into Linus's tree?

Re: [PATCH V7 4/5] scsi: storvsc: Add Isolation VM support for storvsc driver

[Jakub Kicinski]

On Thu, 3 Feb 2022 15:53:51 -0800 Jakub Kicinski wrote:
> On Mon, 13 Dec 2021 02:14:05 -0500 Tianyu Lan wrote:
> > @@ -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);  
> 
> This breaks the x86 clang allmodconfig build as I presume those
> involved know by now:
> 
> ../drivers/hv/vmbus_drv.c:2082:29: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
> static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
>                             ^~~~~~~~~~~~~~~~
> ../include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
> #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
>                                                      ^ ~~~
> 1 error generated.

Looks like a compiler issue actually, found the discussion now:

https://lore.kernel.org/llvm/202112181827.o3X7GmHz-lkp@intel.com/