From adc7b226b7d675d011fe86447a5a36b932f1b061 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 28 Jul 2023 18:35:09 -0700 Subject: [PATCH] drm/i915/gvt: Verify hugepages are contiguous in physical address space When shadowing a GTT entry with a 2M page, verify that the pfns are contiguous, not just that the struct page pointers are contiguous. The memory map is virtual contiguous if "CONFIG_FLATMEM=y || CONFIG_SPARSEMEM_VMEMMAP=y", but not for "CONFIG_SPARSEMEM=y && CONFIG_SPARSEMEM_VMEMMAP=n", so theoretically KVMGT could encounter struct pages that are virtually contiguous, but not physically contiguous. In practice, this flaw is likely a non-issue as it would cause functional problems iff a section isn't 2M aligned _and_ is directly adjacent to another section with discontiguous pfns. Tested-by: Yongwei Ma Reviewed-by: Zhi Wang Reviewed-by: Yan Zhao Link: https://lore.kernel.org/r/20230729013535.1070024-4-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index de675d799c7d..429f0f993a13 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -161,7 +161,7 @@ static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, if (npage == 0) base_page = cur_page; - else if (base_page + npage != cur_page) { + else if (page_to_pfn(base_page) + npage != page_to_pfn(cur_page)) { gvt_vgpu_err("The pages are not continuous\n"); ret = -EINVAL; npage++; -- 2.34.1