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authorPaul Mackerras <paulus@samba.org>2011-12-12 12:32:27 +0000
committerAvi Kivity <avi@redhat.com>2012-03-05 14:52:37 +0200
commit9d0ef5ea043d1242897d15c71bd1a15da79b4a5d (patch)
tree2847b3bd444b999f3c2a32d4cbb220d0e788e93a /arch/powerpc/kvm
parentda9d1d7f2875cc8c1ffbce8f3501d0b33f4e7a4d (diff)
downloadop-kernel-dev-9d0ef5ea043d1242897d15c71bd1a15da79b4a5d.zip
op-kernel-dev-9d0ef5ea043d1242897d15c71bd1a15da79b4a5d.tar.gz
KVM: PPC: Allow I/O mappings in memory slots
This provides for the case where userspace maps an I/O device into the address range of a memory slot using a VM_PFNMAP mapping. In that case, we work out the pfn from vma->vm_pgoff, and record the cache enable bits from vma->vm_page_prot in two low-order bits in the slot_phys array entries. Then, in kvmppc_h_enter() we check that the cache bits in the HPTE that the guest wants to insert match the cache bits in the slot_phys array entry. However, we do allow the guest to create what it thinks is a non-cacheable or write-through mapping to memory that is actually cacheable, so that we can use normal system memory as part of an emulated device later on. In that case the actual HPTE we insert is a cacheable HPTE. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/powerpc/kvm')
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu_hv.c65
-rw-r--r--arch/powerpc/kvm/book3s_hv_rm_mmu.c15
2 files changed, 56 insertions, 24 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index cc18f3d..b904c40 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -199,7 +199,8 @@ static long kvmppc_get_guest_page(struct kvm *kvm, unsigned long gfn,
struct page *page, *hpage, *pages[1];
unsigned long s, pgsize;
unsigned long *physp;
- unsigned int got, pgorder;
+ unsigned int is_io, got, pgorder;
+ struct vm_area_struct *vma;
unsigned long pfn, i, npages;
physp = kvm->arch.slot_phys[memslot->id];
@@ -208,34 +209,51 @@ static long kvmppc_get_guest_page(struct kvm *kvm, unsigned long gfn,
if (physp[gfn - memslot->base_gfn])
return 0;
+ is_io = 0;
+ got = 0;
page = NULL;
pgsize = psize;
+ err = -EINVAL;
start = gfn_to_hva_memslot(memslot, gfn);
/* Instantiate and get the page we want access to */
np = get_user_pages_fast(start, 1, 1, pages);
- if (np != 1)
- return -EINVAL;
- page = pages[0];
- got = KVMPPC_GOT_PAGE;
+ if (np != 1) {
+ /* Look up the vma for the page */
+ down_read(&current->mm->mmap_sem);
+ vma = find_vma(current->mm, start);
+ if (!vma || vma->vm_start > start ||
+ start + psize > vma->vm_end ||
+ !(vma->vm_flags & VM_PFNMAP))
+ goto up_err;
+ is_io = hpte_cache_bits(pgprot_val(vma->vm_page_prot));
+ pfn = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
+ /* check alignment of pfn vs. requested page size */
+ if (psize > PAGE_SIZE && (pfn & ((psize >> PAGE_SHIFT) - 1)))
+ goto up_err;
+ up_read(&current->mm->mmap_sem);
- /* See if this is a large page */
- s = PAGE_SIZE;
- if (PageHuge(page)) {
- hpage = compound_head(page);
- s <<= compound_order(hpage);
- /* Get the whole large page if slot alignment is ok */
- if (s > psize && slot_is_aligned(memslot, s) &&
- !(memslot->userspace_addr & (s - 1))) {
- start &= ~(s - 1);
- pgsize = s;
- page = hpage;
+ } else {
+ page = pages[0];
+ got = KVMPPC_GOT_PAGE;
+
+ /* See if this is a large page */
+ s = PAGE_SIZE;
+ if (PageHuge(page)) {
+ hpage = compound_head(page);
+ s <<= compound_order(hpage);
+ /* Get the whole large page if slot alignment is ok */
+ if (s > psize && slot_is_aligned(memslot, s) &&
+ !(memslot->userspace_addr & (s - 1))) {
+ start &= ~(s - 1);
+ pgsize = s;
+ page = hpage;
+ }
}
+ if (s < psize)
+ goto out;
+ pfn = page_to_pfn(page);
}
- err = -EINVAL;
- if (s < psize)
- goto out;
- pfn = page_to_pfn(page);
npages = pgsize >> PAGE_SHIFT;
pgorder = __ilog2(npages);
@@ -243,7 +261,8 @@ static long kvmppc_get_guest_page(struct kvm *kvm, unsigned long gfn,
spin_lock(&kvm->arch.slot_phys_lock);
for (i = 0; i < npages; ++i) {
if (!physp[i]) {
- physp[i] = ((pfn + i) << PAGE_SHIFT) + got + pgorder;
+ physp[i] = ((pfn + i) << PAGE_SHIFT) +
+ got + is_io + pgorder;
got = 0;
}
}
@@ -257,6 +276,10 @@ static long kvmppc_get_guest_page(struct kvm *kvm, unsigned long gfn,
put_page(page);
}
return err;
+
+ up_err:
+ up_read(&current->mm->mmap_sem);
+ return err;
}
/*
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index c086eb0..3f5b016 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -65,6 +65,7 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long g_ptel = ptel;
struct kvm_memory_slot *memslot;
unsigned long *physp, pte_size;
+ unsigned long is_io;
bool realmode = vcpu->arch.vcore->vcore_state == VCORE_RUNNING;
psize = hpte_page_size(pteh, ptel);
@@ -92,6 +93,7 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
pa = *physp;
if (!pa)
return H_TOO_HARD;
+ is_io = pa & (HPTE_R_I | HPTE_R_W);
pte_size = PAGE_SIZE << (pa & KVMPPC_PAGE_ORDER_MASK);
pa &= PAGE_MASK;
@@ -104,9 +106,16 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
ptel |= pa;
/* Check WIMG */
- if ((ptel & HPTE_R_WIMG) != HPTE_R_M &&
- (ptel & HPTE_R_WIMG) != (HPTE_R_W | HPTE_R_I | HPTE_R_M))
- return H_PARAMETER;
+ if (!hpte_cache_flags_ok(ptel, is_io)) {
+ if (is_io)
+ return H_PARAMETER;
+ /*
+ * Allow guest to map emulated device memory as
+ * uncacheable, but actually make it cacheable.
+ */
+ ptel &= ~(HPTE_R_W|HPTE_R_I|HPTE_R_G);
+ ptel |= HPTE_R_M;
+ }
pteh &= ~0x60UL;
pteh |= HPTE_V_VALID;
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