Commit 5731aacd authored Aug 26, 2024 by Peter Xu Committed by Andrew Morton Sep 17, 2024

KVM: use follow_pfnmap API

Use the new pfnmap API to allow huge MMIO mappings for VMs.  The rest work
is done perfectly on the other side (host_pfn_mapping_level()).

Link: https://lkml.kernel.org/r/20240826204353.2228736-11-peterx@redhat.com


Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 6da8e963

virt/kvm/kvm_main.c

+7 −12

Original line number	Diff line number	Diff line
		@@ -2860,13 +2860,11 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
		unsigned long addr, bool write_fault,
		bool writable, kvm_pfn_t p_pfn)
		{
		struct follow_pfnmap_args args = { .vma = vma, .address = addr };
		kvm_pfn_t pfn;
		pte_t *ptep;
		pte_t pte;
		spinlock_t *ptl;
		int r;

		r = follow_pte(vma, addr, &ptep, &ptl);
		r = follow_pfnmap_start(&args);
		if (r) {
		/*
		* get_user_pages fails for VM_IO and VM_PFNMAP vmas and does
		@@ -2881,21 +2879,19 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
		if (r)
		return r;

		r = follow_pte(vma, addr, &ptep, &ptl);
		r = follow_pfnmap_start(&args);
		if (r)
		return r;
		}

		pte = ptep_get(ptep);

		if (write_fault && !pte_write(pte)) {
		if (write_fault && !args.writable) {
		pfn = KVM_PFN_ERR_RO_FAULT;
		goto out;
		}

		if (writable)
		*writable = pte_write(pte);
		pfn = pte_pfn(pte);
		*writable = args.writable;
		pfn = args.pfn;

		/*
		* Get a reference here because callers of hva_to_pfn and
		@@ -2916,9 +2912,8 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
		*/
		if (!kvm_try_get_pfn(pfn))
		r = -EFAULT;

		out:
		pte_unmap_unlock(ptep, ptl);
		follow_pfnmap_end(&args);
		*p_pfn = pfn;

		return r;