[RFC PATCH 07/11] KVM: PPC: Convert do_h_register_vpa to use Linux page

Paul Mackerras
2011-11-16T23:02:06Z

This makes do_h_register_vpa use a new helper function,
kvmppc_pin_guest_page, to pin the page containing the virtual
processor area that the guest wants to register. The logic of
whether to use the userspace Linux page tables or the slot_pfns
array is thus hidden in kvmppc_pin_guest_page. There is also a
new kvmppc_unpin_guest_page to release a previously-pinned page,
which we call at VPA unregistration time, or when a new VPA is
registered, or when the vcpu is destroyed.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/include/asm/kvm_book3s.h | 3 ++
arch/powerpc/kvm/book3s_64_mmu_hv.c | 44 +++++++++++++++++++++++++++
arch/powerpc/kvm/book3s_hv.c | 52 ++++++++++++++++++++++----------
3 files changed, 83 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index bd8345f..b5ee1ce 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -141,6 +141,9 @@ extern void kvmppc_set_bat(struct kvm_vcpu *vcpu, struct kvmppc_bat *bat,
extern void kvmppc_giveup_ext(struct kvm_vcpu *vcpu, ulong msr);
extern int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu);
extern pfn_t kvmppc_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn);
+extern void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long addr,
+ unsigned long *nb_ret);
+extern void kvmppc_unpin_guest_page(struct kvm *kvm, void *addr);

extern void kvmppc_entry_trampoline(void);
extern void kvmppc_hv_entry_trampoline(void);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 99187db..9c7e825 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -480,6 +480,50 @@ int kvmppc_book3s_hv_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu)
return kvmppc_emulate_mmio(run, vcpu);
}

+void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long gpa,
+ unsigned long *nb_ret)
+{
+ struct kvm_memory_slot *memslot;
+ unsigned long gfn = gpa >> PAGE_SHIFT;
+ struct page *pages[1];
+ int npages;
+ unsigned long hva, psize, offset;
+ unsigned long pfn;
+ unsigned long *pfnp;
+
+ memslot = gfn_to_memslot(kvm, gfn);
+ if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID) ||
+ (memslot->flags & KVM_MEMSLOT_IO))
+ return NULL;
+ pfnp = kvmppc_pfn_entry(kvm, memslot, gfn);
+ if (pfnp) {
+ pfn = *pfnp;
+ if (!pfn)
+ return NULL;
+ psize = 1ul << kvm->arch.slot_page_order[memslot->id];
+ pages[0] = pfn_to_page(pfn);
+ get_page(pages[0]);
+ } else {
+ hva = gfn_to_hva_memslot(memslot, gfn);
+ npages = get_user_pages_fast(hva, 1, 1, pages);
+ if (npages < 1)
+ return NULL;
+ psize = PAGE_SIZE;
+ }
+ offset = gpa & (psize - 1);
+ if (nb_ret)
+ *nb_ret = psize - offset;
+ return page_address(pages[0]) + offset;
+}
+
+void kvmppc_unpin_guest_page(struct kvm *kvm, void *va)
+{
+ struct page *page = virt_to_page(va);
+
+ page = compound_head(page);
+ put_page(page);
+}
+
void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
{
struct kvmppc_mmu *mmu = &vcpu->arch.mmu;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index cb21845..ceb49d2 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -163,10 +163,10 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
unsigned long vcpuid, unsigned long vpa)
{
struct kvm *kvm = vcpu->kvm;
- unsigned long ra, len;
- unsigned long nb;
+ unsigned long len, nb;
void *va;
struct kvm_vcpu *tvcpu;
+ int err = H_PARAMETER;

tvcpu = kvmppc_find_vcpu(kvm, vcpuid);
if (!tvcpu)
@@ -179,40 +179,41 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
if (flags < 4) {
if (vpa & 0x7f)
return H_PARAMETER;
+ if (flags >= 2 && !tvcpu->arch.vpa)
+ return H_RESOURCE;
/* registering new area; convert logical addr to real */
- ra = kvmppc_logical_to_real(kvm, vpa, &nb);
- if (!ra)
+ va = kvmppc_pin_guest_page(kvm, vpa, &nb);
+ if (va = NULL)
return H_PARAMETER;
- va = __va(ra);
if (flags <= 1)
len = *(unsigned short *)(va + 4);
else
len = *(unsigned int *)(va + 4);
if (len > nb)
- return H_PARAMETER;
+ goto out_unpin;
switch (flags) {
case 1: /* register VPA */
if (len < 640)
- return H_PARAMETER;
+ goto out_unpin;
+ if (tvcpu->arch.vpa)
+ kvmppc_unpin_guest_page(kvm, vcpu->arch.vpa);
tvcpu->arch.vpa = va;
init_vpa(vcpu, va);
break;
case 2: /* register DTL */
if (len < 48)
- return H_PARAMETER;
- if (!tvcpu->arch.vpa)
- return H_RESOURCE;
+ goto out_unpin;
len -= len % 48;
+ if (tvcpu->arch.dtl)
+ kvmppc_unpin_guest_page(kvm, vcpu->arch.dtl);
tvcpu->arch.dtl = va;
tvcpu->arch.dtl_end = va + len;
break;
case 3: /* register SLB shadow buffer */
- if (len < 8)
- return H_PARAMETER;
- if (!tvcpu->arch.vpa)
- return H_RESOURCE;
- tvcpu->arch.slb_shadow = va;
- len = (len - 16) / 16;
+ if (len < 16)
+ goto out_unpin;
+ if (tvcpu->arch.slb_shadow)
+ kvmppc_unpin_guest_page(kvm, vcpu->arch.slb_shadow);
tvcpu->arch.slb_shadow = va;
break;
}
@@ -221,17 +222,30 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
case 5: /* unregister VPA */
if (tvcpu->arch.slb_shadow || tvcpu->arch.dtl)
return H_RESOURCE;
+ if (!tvcpu->arch.vpa)
+ break;
+ kvmppc_unpin_guest_page(kvm, tvcpu->arch.vpa);
tvcpu->arch.vpa = NULL;
break;
case 6: /* unregister DTL */
+ if (!tvcpu->arch.dtl)
+ break;
+ kvmppc_unpin_guest_page(kvm, tvcpu->arch.dtl);
tvcpu->arch.dtl = NULL;
break;
case 7: /* unregister SLB shadow buffer */
+ if (!tvcpu->arch.slb_shadow)
+ break;
+ kvmppc_unpin_guest_page(kvm, tvcpu->arch.slb_shadow);
tvcpu->arch.slb_shadow = NULL;
break;
}
}
return H_SUCCESS;
+
+ out_unpin:
+ kvmppc_unpin_guest_page(kvm, va);
+ return err;
}

int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
@@ -488,6 +502,12 @@ out:

void kvmppc_core_vcpu_free(struct kvm_vcpu *vcpu)
{
+ if (vcpu->arch.dtl)
+ kvmppc_unpin_guest_page(vcpu->kvm, vcpu->arch.dtl);
+ if (vcpu->arch.slb_shadow)
+ kvmppc_unpin_guest_page(vcpu->kvm, vcpu->arch.slb_shadow);
+ if (vcpu->arch.vpa)
+ kvmppc_unpin_guest_page(vcpu->kvm, vcpu->arch.vpa);
kvm_vcpu_uninit(vcpu);
kfree(vcpu);
}
--
1.7.7.2