| Message ID | 20210809175620.720923-12-ltykernel@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | x86/Hyper-V: Add Hyper-V Isolation VM support | expand |
From: Tianyu Lan <ltykernel@gmail.com> Sent: Monday, August 9, 2021 10:56 AM > > Hyper-V 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 dma_map_decrypted() > to mark bounce buffer visible to host and map it in extra > address space. Populate dma memory decrypted ops with hv > map/unmap function. > > 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. > > The map function vmap_pfn() can't work in the early place > hyperv_iommu_swiotlb_init() and so initialize swiotlb bounce > buffer in the hyperv_iommu_swiotlb_later_init(). > > Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> > --- > arch/x86/hyperv/ivm.c | 28 ++++++++++++++ > arch/x86/include/asm/mshyperv.h | 2 + > arch/x86/xen/pci-swiotlb-xen.c | 3 +- > drivers/hv/vmbus_drv.c | 3 ++ > drivers/iommu/hyperv-iommu.c | 65 +++++++++++++++++++++++++++++++++ > include/linux/hyperv.h | 1 + > 6 files changed, 101 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c > index c13ec5560d73..0f05e4d6fc62 100644 > --- a/arch/x86/hyperv/ivm.c > +++ b/arch/x86/hyperv/ivm.c > @@ -265,3 +265,31 @@ int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible) > > return __hv_set_mem_host_visibility((void *)addr, numpages, visibility); > } > + > +/* > + * 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 / HV_HYP_PAGE_SIZE; i++) > + pfns[i] = virt_to_hvpfn(addr + i * HV_HYP_PAGE_SIZE) + > + (ms_hyperv.shared_gpa_boundary >> HV_HYP_PAGE_SHIFT); > + > + vaddr = vmap_pfn(pfns, size / HV_HYP_PAGE_SIZE, PAGE_KERNEL_IO); > + kfree(pfns); > + > + return vaddr; > +} This function is manipulating page tables in the guest VM. It is not involved in communicating with Hyper-V, or passing PFNs to Hyper-V. The pfn array contains guest PFNs, not Hyper-V PFNs. So it should use PAGE_SIZE instead of HV_HYP_PAGE_SIZE, and similarly PAGE_SHIFT and virt_to_pfn(). If this code were ever to run on ARM64 in the future with PAGE_SIZE other than 4 Kbytes, the use of PAGE_SIZE is correct choice. > + > +void hv_unmap_memory(void *addr) > +{ > + vunmap(addr); > +} > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index a30c60f189a3..b247739f57ac 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -250,6 +250,8 @@ int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry); > int hv_mark_gpa_visibility(u16 count, const u64 pfn[], > enum hv_mem_host_visibility visibility); > int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible); > +void *hv_map_memory(void *addr, unsigned long size); > +void hv_unmap_memory(void *addr); > void hv_sint_wrmsrl_ghcb(u64 msr, u64 value); > void hv_sint_rdmsrl_ghcb(u64 msr, u64 *value); > void hv_signal_eom_ghcb(void); > diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c > index 54f9aa7e8457..43bd031aa332 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 57bbbaa4e8f7..f068e22a5636 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -23,6 +23,7 @@ > #include <linux/cpu.h> > #include <linux/sched/task_stack.h> > > +#include <linux/dma-map-ops.h> > #include <linux/delay.h> > #include <linux/notifier.h> > #include <linux/panic_notifier.h> > @@ -2081,6 +2082,7 @@ 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 > */ > @@ -2121,6 +2123,7 @@ 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..01e874b3b43a 100644 > --- a/drivers/iommu/hyperv-iommu.c > +++ b/drivers/iommu/hyperv-iommu.c > @@ -13,14 +13,22 @@ > #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-map-ops.h> > +#include <linux/dma-direct.h> > +#include <linux/set_memory.h> > > #include "irq_remapping.h" > > @@ -36,6 +44,9 @@ > static cpumask_t ioapic_max_cpumask = { CPU_BITS_NONE }; > static struct irq_domain *ioapic_ir_domain; > > +static unsigned long hyperv_io_tlb_size; > +static void *hyperv_io_tlb_start; > + > static int hyperv_ir_set_affinity(struct irq_data *data, > const struct cpumask *mask, bool force) > { > @@ -337,4 +348,58 @@ static const struct irq_domain_ops hyperv_root_ir_domain_ops = { > .free = hyperv_root_irq_remapping_free, > }; > > +void __init hyperv_iommu_swiotlb_init(void) > +{ > + unsigned long bytes; > + > + /* > + * Allocate Hyper-V swiotlb bounce buffer at early place > + * to reserve large contiguous memory. > + */ > + hyperv_io_tlb_size = 256 * 1024 * 1024; A hard coded size here seems problematic. The memory size of Isolated VMs can vary by orders of magnitude. I see that xen_swiotlb_init() uses swiotlb_size_or_default(), which at least pays attention to the value specified on the kernel boot line. Another example is sev_setup_arch(), which in the native case sets the size to 6% of main memory, with a max of 1 Gbyte. This is the case that's closer to Isolated VMs, so doing something similar could be a good approach. > + hyperv_io_tlb_start = > + memblock_alloc_low( > + PAGE_ALIGN(hyperv_io_tlb_size), > + HV_HYP_PAGE_SIZE); > + > + if (!hyperv_io_tlb_start) { > + pr_warn("Fail to allocate Hyper-V swiotlb buffer.\n"); > + return; > + } > +} > + > +int __init hyperv_swiotlb_detect(void) > +{ > + if (hypervisor_is_type(X86_HYPER_MS_HYPERV) > + && hv_is_isolation_supported()) { > + /* > + * Enable swiotlb force mode in Isolation VM to > + * use swiotlb bounce buffer for dma transaction. > + */ > + swiotlb_force = SWIOTLB_FORCE; > + > + dma_memory_generic_decrypted_ops.map = hv_map_memory; > + dma_memory_generic_decrypted_ops.unmap = hv_unmap_memory; > + return 1; > + } > + > + return 0; > +} > + > +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_late_init_with_tbl() here. > + */ > + if (swiotlb_late_init_with_tbl(hyperv_io_tlb_start, > + hyperv_io_tlb_size >> IO_TLB_SHIFT)) > + panic("Fail to initialize hyperv swiotlb.\n"); > +} > + > +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 90b542597143..83fa567ad594 100644 > --- a/include/linux/hyperv.h > +++ b/include/linux/hyperv.h > @@ -1744,6 +1744,7 @@ 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)); > +int __init hyperv_swiotlb_detect(void); > > struct hyperv_pci_block_ops { > int (*read_block)(struct pci_dev *dev, void *buf, unsigned int buf_len, > -- > 2.25.1
On Thu, Aug 19, 2021 at 06:11:30PM +0000, Michael Kelley wrote: > This function is manipulating page tables in the guest VM. It is not involved > in communicating with Hyper-V, or passing PFNs to Hyper-V. The pfn array > contains guest PFNs, not Hyper-V PFNs. So it should use PAGE_SIZE > instead of HV_HYP_PAGE_SIZE, and similarly PAGE_SHIFT and virt_to_pfn(). > If this code were ever to run on ARM64 in the future with PAGE_SIZE other > than 4 Kbytes, the use of PAGE_SIZE is correct choice. Yes. I just stumled over this yesterday. I think we can actually use a nicer helper ased around vmap_range() to simplify this exactly because it always uses the host page size. I hope I can draft up a RFC today.
On 8/20/2021 2:11 AM, Michael Kelley 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, >> + sizeof(unsigned long), GFP_KERNEL); >> + void *vaddr; >> + int i; >> + >> + if (!pfns) >> + return NULL; >> + >> + for (i = 0; i < size / HV_HYP_PAGE_SIZE; i++) >> + pfns[i] = virt_to_hvpfn(addr + i * HV_HYP_PAGE_SIZE) + >> + (ms_hyperv.shared_gpa_boundary >> HV_HYP_PAGE_SHIFT); >> + >> + vaddr = vmap_pfn(pfns, size / HV_HYP_PAGE_SIZE, PAGE_KERNEL_IO); >> + kfree(pfns); >> + >> + return vaddr; >> +} > This function is manipulating page tables in the guest VM. It is not involved > in communicating with Hyper-V, or passing PFNs to Hyper-V. The pfn array > contains guest PFNs, not Hyper-V PFNs. So it should use PAGE_SIZE > instead of HV_HYP_PAGE_SIZE, and similarly PAGE_SHIFT and virt_to_pfn(). > If this code were ever to run on ARM64 in the future with PAGE_SIZE other > than 4 Kbytes, the use of PAGE_SIZE is correct choice. OK. Will update with PAGE_SIZE. > >> +void __init hyperv_iommu_swiotlb_init(void) >> +{ >> + unsigned long bytes; >> + >> + /* >> + * Allocate Hyper-V swiotlb bounce buffer at early place >> + * to reserve large contiguous memory. >> + */ >> + hyperv_io_tlb_size = 256 * 1024 * 1024; > A hard coded size here seems problematic. The memory size of > Isolated VMs can vary by orders of magnitude. I see that > xen_swiotlb_init() uses swiotlb_size_or_default(), which at least > pays attention to the value specified on the kernel boot line. > > Another example is sev_setup_arch(), which in the native case sets > the size to 6% of main memory, with a max of 1 Gbyte. This is > the case that's closer to Isolated VMs, so doing something > similar could be a good approach. > Yes, agree. It's better to keep bounce buffer size with AMD SEV.
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index c13ec5560d73..0f05e4d6fc62 100644 --- a/arch/x86/hyperv/ivm.c +++ b/arch/x86/hyperv/ivm.c @@ -265,3 +265,31 @@ int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible) return __hv_set_mem_host_visibility((void *)addr, numpages, visibility); } + +/* + * 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 / HV_HYP_PAGE_SIZE; i++) + pfns[i] = virt_to_hvpfn(addr + i * HV_HYP_PAGE_SIZE) + + (ms_hyperv.shared_gpa_boundary >> HV_HYP_PAGE_SHIFT); + + vaddr = vmap_pfn(pfns, size / HV_HYP_PAGE_SIZE, PAGE_KERNEL_IO); + kfree(pfns); + + return vaddr; +} + +void hv_unmap_memory(void *addr) +{ + vunmap(addr); +} diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index a30c60f189a3..b247739f57ac 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -250,6 +250,8 @@ int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry); int hv_mark_gpa_visibility(u16 count, const u64 pfn[], enum hv_mem_host_visibility visibility); int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible); +void *hv_map_memory(void *addr, unsigned long size); +void hv_unmap_memory(void *addr); void hv_sint_wrmsrl_ghcb(u64 msr, u64 value); void hv_sint_rdmsrl_ghcb(u64 msr, u64 *value); void hv_signal_eom_ghcb(void); diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c index 54f9aa7e8457..43bd031aa332 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 57bbbaa4e8f7..f068e22a5636 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -23,6 +23,7 @@ #include <linux/cpu.h> #include <linux/sched/task_stack.h> +#include <linux/dma-map-ops.h> #include <linux/delay.h> #include <linux/notifier.h> #include <linux/panic_notifier.h> @@ -2081,6 +2082,7 @@ 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 */ @@ -2121,6 +2123,7 @@ 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..01e874b3b43a 100644 --- a/drivers/iommu/hyperv-iommu.c +++ b/drivers/iommu/hyperv-iommu.c @@ -13,14 +13,22 @@ #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-map-ops.h> +#include <linux/dma-direct.h> +#include <linux/set_memory.h> #include "irq_remapping.h" @@ -36,6 +44,9 @@ static cpumask_t ioapic_max_cpumask = { CPU_BITS_NONE }; static struct irq_domain *ioapic_ir_domain; +static unsigned long hyperv_io_tlb_size; +static void *hyperv_io_tlb_start; + static int hyperv_ir_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force) { @@ -337,4 +348,58 @@ static const struct irq_domain_ops hyperv_root_ir_domain_ops = { .free = hyperv_root_irq_remapping_free, }; +void __init hyperv_iommu_swiotlb_init(void) +{ + unsigned long bytes; + + /* + * Allocate Hyper-V swiotlb bounce buffer at early place + * to reserve large contiguous memory. + */ + hyperv_io_tlb_size = 256 * 1024 * 1024; + hyperv_io_tlb_start = + memblock_alloc_low( + PAGE_ALIGN(hyperv_io_tlb_size), + HV_HYP_PAGE_SIZE); + + if (!hyperv_io_tlb_start) { + pr_warn("Fail to allocate Hyper-V swiotlb buffer.\n"); + return; + } +} + +int __init hyperv_swiotlb_detect(void) +{ + if (hypervisor_is_type(X86_HYPER_MS_HYPERV) + && hv_is_isolation_supported()) { + /* + * Enable swiotlb force mode in Isolation VM to + * use swiotlb bounce buffer for dma transaction. + */ + swiotlb_force = SWIOTLB_FORCE; + + dma_memory_generic_decrypted_ops.map = hv_map_memory; + dma_memory_generic_decrypted_ops.unmap = hv_unmap_memory; + return 1; + } + + return 0; +} + +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_late_init_with_tbl() here. + */ + if (swiotlb_late_init_with_tbl(hyperv_io_tlb_start, + hyperv_io_tlb_size >> IO_TLB_SHIFT)) + panic("Fail to initialize hyperv swiotlb.\n"); +} + +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 90b542597143..83fa567ad594 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1744,6 +1744,7 @@ 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)); +int __init hyperv_swiotlb_detect(void); struct hyperv_pci_block_ops { int (*read_block)(struct pci_dev *dev, void *buf, unsigned int buf_len,