KVM: PPC: Fix dcbz emulation
On most systems we need to emulate dcbz when running 32 bit guests. So
far we've been rather slack, not giving correct DSISR values to the guest.
This patch makes the emulation more accurate, introducing a difference
between "page not mapped" and "write protection fault". While at it, it
also speeds up dcbz emulation by an order of magnitude by using kmap.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index d2b3dab..ed57584 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -29,6 +29,7 @@
#include <linux/gfp.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
+#include <linux/highmem.h>
#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
@@ -369,34 +370,29 @@
*/
static void kvmppc_patch_dcbz(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)
{
- bool touched = false;
- hva_t hpage;
+ struct page *hpage;
+ u64 hpage_offset;
u32 *page;
int i;
- hpage = gfn_to_hva(vcpu->kvm, pte->raddr >> PAGE_SHIFT);
- if (kvm_is_error_hva(hpage))
+ hpage = gfn_to_page(vcpu->kvm, pte->raddr >> PAGE_SHIFT);
+ if (is_error_page(hpage))
return;
- hpage |= pte->raddr & ~PAGE_MASK;
- hpage &= ~0xFFFULL;
+ hpage_offset = pte->raddr & ~PAGE_MASK;
+ hpage_offset &= ~0xFFFULL;
+ hpage_offset /= 4;
- page = vmalloc(HW_PAGE_SIZE);
+ get_page(hpage);
+ page = kmap_atomic(hpage, KM_USER0);
- if (copy_from_user(page, (void __user *)hpage, HW_PAGE_SIZE))
- goto out;
+ /* patch dcbz into reserved instruction, so we trap */
+ for (i=hpage_offset; i < hpage_offset + (HW_PAGE_SIZE / 4); i++)
+ if ((page[i] & 0xff0007ff) == INS_DCBZ)
+ page[i] &= 0xfffffff7;
- for (i=0; i < HW_PAGE_SIZE / 4; i++)
- if ((page[i] & 0xff0007ff) == INS_DCBZ) {
- page[i] &= 0xfffffff7; // reserved instruction, so we trap
- touched = true;
- }
-
- if (touched)
- copy_to_user((void __user *)hpage, page, HW_PAGE_SIZE);
-
-out:
- vfree(page);
+ kunmap_atomic(page, KM_USER0);
+ put_page(hpage);
}
static int kvmppc_xlate(struct kvm_vcpu *vcpu, ulong eaddr, bool data,
@@ -449,30 +445,21 @@
bool data)
{
struct kvmppc_pte pte;
- hva_t hva = *eaddr;
vcpu->stat.st++;
if (kvmppc_xlate(vcpu, *eaddr, data, &pte))
- goto nopte;
+ return -ENOENT;
*eaddr = pte.raddr;
- hva = kvmppc_pte_to_hva(vcpu, &pte, false);
- if (kvm_is_error_hva(hva))
- goto mmio;
+ if (!pte.may_write)
+ return -EPERM;
- if (copy_to_user((void __user *)hva, ptr, size)) {
- printk(KERN_INFO "kvmppc_st at 0x%lx failed\n", hva);
- goto mmio;
- }
+ if (kvm_write_guest(vcpu->kvm, pte.raddr, ptr, size))
+ return EMULATE_DO_MMIO;
return EMULATE_DONE;
-
-nopte:
- return -ENOENT;
-mmio:
- return EMULATE_DO_MMIO;
}
int kvmppc_ld(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr,
@@ -787,6 +774,7 @@
* that no guest that needs the dcbz hack does NX.
*/
kvmppc_mmu_pte_flush(vcpu, vcpu->arch.pc, ~0xFFFULL);
+ r = RESUME_GUEST;
} else {
vcpu->arch.msr |= vcpu->arch.shadow_srr1 & 0x58000000;
kvmppc_book3s_queue_irqprio(vcpu, exit_nr);