[PATCH v0 14/15] mshv: Remove mapping of mmio space during map user ioctl
From: Mukesh R <hidden>
Date: 2026-01-20 06:43:50
Also in:
linux-arch, linux-hyperv, linux-iommu, linux-pci, lkml
Subsystem:
hyper-v/azure core and drivers, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Linus Torvalds
From: Mukesh Rathor <redacted> VFIO no longer puts the mmio pfn in vma->vm_pgoff. So, remove code that is using it to map mmio space. It is broken and will cause panic. Signed-off-by: Mukesh Rathor <redacted> --- drivers/hv/mshv_root_main.c | 20 ++++---------------- 1 file changed, 4 insertions(+), 16 deletions(-)
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index 27313419828d..03f3aa9f5541 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c@@ -1258,16 +1258,8 @@ static int mshv_prepare_pinned_region(struct mshv_mem_region *region) } /* - * This maps two things: guest RAM and for pci passthru mmio space. - * - * mmio: - * - vfio overloads vm_pgoff to store the mmio start pfn/spa. - * - Two things need to happen for mapping mmio range: - * 1. mapped in the uaddr so VMM can access it. - * 2. mapped in the hwpt (gfn <-> mmio phys addr) so guest can access it. - * - * This function takes care of the second. The first one is managed by vfio, - * and hence is taken care of via vfio_pci_mmap_fault(). + * This is called for both user ram and mmio space. The mmio space is not + * mapped here, but later during intercept. */ static long mshv_map_user_memory(struct mshv_partition *partition,
@@ -1276,7 +1268,6 @@ mshv_map_user_memory(struct mshv_partition *partition, struct mshv_mem_region *region; struct vm_area_struct *vma; bool is_mmio; - ulong mmio_pfn; long ret; if (mem.flags & BIT(MSHV_SET_MEM_BIT_UNMAP) ||
@@ -1286,7 +1277,6 @@ mshv_map_user_memory(struct mshv_partition *partition, mmap_read_lock(current->mm); vma = vma_lookup(current->mm, mem.userspace_addr); is_mmio = vma ? !!(vma->vm_flags & (VM_IO | VM_PFNMAP)) : 0; - mmio_pfn = is_mmio ? vma->vm_pgoff : 0; mmap_read_unlock(current->mm); if (!vma)
@@ -1313,10 +1303,8 @@ mshv_map_user_memory(struct mshv_partition *partition, HV_MAP_GPA_NO_ACCESS, NULL); break; case MSHV_REGION_TYPE_MMIO: - ret = hv_call_map_mmio_pages(partition->pt_id, - region->start_gfn, - mmio_pfn, - region->nr_pages); + /* mmio mappings are handled later during intercepts */ + ret = 0; break; }
--
2.51.2.vfs.0.1