/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright IBM Corp. 2007
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
*/
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <asm/mmu-44x.h>
#include <asm/kvm_ppc.h>
#include "44x_tlb.h"
#define PPC44x_TLB_USER_PERM_MASK (PPC44x_TLB_UX|PPC44x_TLB_UR|PPC44x_TLB_UW)
#define PPC44x_TLB_SUPER_PERM_MASK (PPC44x_TLB_SX|PPC44x_TLB_SR|PPC44x_TLB_SW)
static unsigned int kvmppc_tlb_44x_pos;
static u32 kvmppc_44x_tlb_shadow_attrib(u32 attrib, int usermode)
{
/* Mask off reserved bits. */
attrib &= PPC44x_TLB_PERM_MASK|PPC44x_TLB_ATTR_MASK;
if (!usermode) {
/* Guest is in supervisor mode, so we need to translate guest
* supervisor permissions into user permissions. */
attrib &= ~PPC44x_TLB_USER_PERM_MASK;
attrib |= (attrib & PPC44x_TLB_SUPER_PERM_MASK) << 3;
}
/* Make sure host can always access this memory. */
attrib |= PPC44x_TLB_SX|PPC44x_TLB_SR|PPC44x_TLB_SW;
return attrib;
}
/* Search the guest TLB for a matching entry. */
int kvmppc_44x_tlb_index(struct kvm_vcpu *vcpu, gva_t eaddr, unsigned int pid,
unsigned int as)
{
int i;
/* XXX Replace loop with fancy data structures. */
for (i = 0; i < PPC44x_TLB_SIZE; i++) {
struct tlbe *tlbe = &vcpu->arch.guest_tlb[i];
unsigned int tid;
if (eaddr < get_tlb_eaddr(tlbe))
continue;
if (eaddr > get_tlb_end(tlbe))
continue;
tid = get_tlb_tid(tlbe);
if (tid && (tid != pid))
continue;
if (!get_tlb_v(tlbe))
continue;
if (get_tlb_ts(tlbe) != as)
continue;
return i;
}
return -1;
}
struct tlbe *kvmppc_44x_itlb_search(struct kvm_vcpu *vcpu, gva_t eaddr)
{
unsigned int as = !!(vcpu->arch.msr & MSR_IS);
unsigned int index;
index = kvmppc_44x_tlb_index(vcpu, eaddr, vcpu->arch.pid, as);
if (index == -1)
return NULL;
return &vcpu->arch.guest_tlb[index];
}
struct tlbe *kvmppc_44x_dtlb_search(struct kvm_vcpu *vcpu, gva_t eaddr)
{
unsigned int as = !!(vcpu->arch.msr & MSR_DS);
unsigned int index;
index = kvmppc_44x_tlb_index(vcpu, eaddr, vcpu->arch.pid, as);
if (index == -1)
return NULL;
return &vcpu->arch.guest_tlb[index];
}
static int kvmppc_44x_tlbe_is_writable(struct tlbe *tlbe)
{
return tlbe->word2 & (PPC44x_TLB_SW|PPC44x_TLB_UW);
}
/* Must be called with mmap_sem locked for writing. */
static void kvmppc_44x_shadow_release(struct kvm_vcpu *vcpu,
unsigned int index)
{
struct tlbe *stlbe = &vcpu->arch.shadow_tlb[index];
struct page *page = vcpu->arch.shadow_pages[index];
if (get_tlb_v(stlbe)) {
if (kvmppc_44x_tlbe_is_writable(stlbe))
kvm_release_page_dirty(page);
else
kvm_release_page_clean(page);
}
}
/* Caller must ensure that the specified guest TLB entry is safe to insert into
* the shadow TLB. */
void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 gvaddr, gfn_t gfn, u64 asid,
u32 flags)
{
struct page *new_page;
struct tlbe *stlbe;
hpa_t hpaddr;
unsigned int victim;
/* Future optimization: don't overwrite the TLB entry containing the
* current PC (or stack?). */
victim = kvmppc_tlb_44x_pos++;
if (kvmppc_tlb_44x_pos > tlb_44x_hwater)
kvmppc_tlb_44x_pos = 0;
stlbe = &vcpu->arch.shadow_tlb[victim];
/* Get reference to new page. */
down_read(¤t->mm->mmap_sem);
new_page = gfn_to_page(vcpu->kvm, gfn);
if (is_error_page(new_page)) {
printk(KERN_ERR "Couldn't get guest page for gfn %lx!\n", gfn);
kvm_release_page_clean(new_page);
up_read(¤t->mm->mmap_sem);
return;
}
hpaddr = page_to_phys(new_page);
/* Drop reference to old page. */
kvmppc_44x_shadow_release(vcpu, victim);
up_read(¤t->mm->mmap_sem);
vcpu->arch.shadow_pages[victim] = new_page;
/* XXX Make sure (va, size) doesn't overlap any other
* entries. 440x6 user manual says the result would be
* "undefined." */
/* XXX what about AS? */
stlbe->tid = asid & 0xff;
/* Force TS=1 for all guest mappings. */
/* For now we hardcode 4KB mappings, but it will be important to
* use host large pages in the future. */
stlbe->word0 = (gvaddr & PAGE_MASK) | PPC44x_TLB_VALID | PPC44x_TLB_TS
| PPC44x_TLB_4K;
stlbe->word1 = (hpaddr & 0xfffffc00) | ((hpaddr >> 32) & 0xf);
stlbe->word2 = kvmppc_44x_tlb_shadow_attrib(flags,
vcpu->arch.msr & MSR_PR);
}
void kvmppc_mmu_invalidate(struct kvm_vcpu *vcpu, u64 eaddr, u64 asid)
{
unsigned int pid = asid & 0xff;
int i;
/* XXX Replace loop with fancy data structures. */
down_write(¤t->mm->mmap_sem);
for (i = 0; i <= tlb_44x_hwater; i++) {
struct tlbe *stlbe = &vcpu->arch.shadow_tlb[i];
unsigned int tid;
if (!get_tlb_v(stlbe))
continue;
if (eaddr < get_tlb_eaddr(stlbe))
continue;
if (eaddr > get_tlb_end(stlbe))
continue;
tid = get_tlb_tid(stlbe);
if (tid && (tid != pid))
continue;
kvmppc_44x_shadow_release(vcpu, i);
stlbe->word0 = 0;
}
up_write(¤t->mm->mmap_sem);
}
/* Invalidate all mappings, so that when they fault back in they will get the
* proper permission bits. */
void kvmppc_mmu_priv_switch(struct kvm_vcpu *vcpu, int usermode)
{
int i;
/* XXX Replace loop with fancy data structures. */
down_write(¤t->mm->mmap_sem);
for (i = 0; i <= tlb_44x_hwater; i++) {
kvmppc_44x_shadow_release(vcpu, i);
vcpu->arch.shadow_tlb[i].word0 = 0;
}
up_write(¤t->mm->mmap_sem);
}
