--- v2
+++ v4
@@ -1,50 +1,209 @@
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.
+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/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)
+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/xen/pci-swiotlb-xen.c | 12 ++++++-
+ drivers/hv/vmbus_drv.c | 3 ++
+ drivers/iommu/hyperv-iommu.c | 58 ++++++++++++++++++++++++++++++++++
+ include/linux/hyperv.h | 8 +++++
+ 4 files changed, 80 insertions(+), 1 deletion(-)
+
+diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
+index 46df59aeaa06..8e2ee3ce6374 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>
+@@ -90,7 +91,16 @@ int pci_xen_swiotlb_init_late(void)
+ }
+ EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
+
++/*
++ * 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.
++ */
+ 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..44ba24d9e06c 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 +343,56 @@ 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");
++ return;
++ }
++
++ 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
- }
-
-+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;
+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
-+ return false;
++static inline int __init hyperv_swiotlb_detect(void)
++{
++ return 0;
++}
+#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);
-
+
+ struct hyperv_pci_block_ops {
+ int (*read_block)(struct pci_dev *dev, void *buf, unsigned int buf_len,
--
2.25.1