xen: adjust early dom0 p2m handling to xen hypervisor behavior (69861e0a) · Commits · 戴 / test

When booted as pv-guest the p2m list presented by the Xen is already mapped to virtual addresses. In dom0 case the hypervisor might make use of 2M- or 1G-pages for this mapping. Unfortunately while being properly aligned in virtual and machine address space, those pages might not be aligned properly in guest physical address space. So when trying to obtain the guest physical address of such a page pud_pfn() and pmd_pfn() must be avoided as those will mask away guest physical address bits not being zero in this special case. Signed-off-by:

Juergen Gross <jgross@suse.com> Reviewed-by:

Jan Beulich <jbeulich@suse.com> Signed-off-by:

Juergen Gross <jgross@suse.com>

arch/x86/xen/mmu_pv.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -2025,7 +2025,8 @@ static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)

		/*
		* Translate a virtual address to a physical one without relying on mapped
		* page tables.
		* page tables. Don't rely on big pages being aligned in (guest) physical
		* space!
		*/
		static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
		{
		@@ -2046,7 +2047,7 @@ static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
		sizeof(pud)));
		if (!pud_present(pud))
		return 0;
		pa = pud_pfn(pud) << PAGE_SHIFT;
		pa = pud_val(pud) & PTE_PFN_MASK;
		if (pud_large(pud))
		return pa + (vaddr & ~PUD_MASK);

		@@ -2054,7 +2055,7 @@ static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
		sizeof(pmd)));
		if (!pmd_present(pmd))
		return 0;
		pa = pmd_pfn(pmd) << PAGE_SHIFT;
		pa = pmd_val(pmd) & PTE_PFN_MASK;
		if (pmd_large(pmd))
		return pa + (vaddr & ~PMD_MASK);

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