When shadowing, we must make sure, that any changes to the GMAP inside
guest N will also be directly reflected in our shadow GMAP. This is
done by write-protecting guest N memory at the places where it stores
DAT tables for guest N + 1.
This still lacks EDAT1 support, so let's add it.
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx>
---
arch/s390/mm/gmap.c | 97 ++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 77 insertions(+), 20 deletions(-)
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 5699770..66789e2 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -1096,6 +1096,18 @@ static void gmap_pmdp_transfer_prot(struct mm_struct *mm, unsigned long addr,
*hpmdp = new;
}
+static void gmap_pte_transfer_prot(struct mm_struct *mm, unsigned long addr,
+ pte_t *gptep, pmd_t *hpmdp)
+{
+ pmd_t mpmd = __pmd(0);
+
+ if (pte_val(*gptep) & _PAGE_PROTECT)
+ pmd_val(mpmd) |= _SEGMENT_ENTRY_PROTECT;
+ if (pte_val(*gptep) & _PAGE_INVALID)
+ pmd_val(mpmd) |= _SEGMENT_ENTRY_INVALID;
+ gmap_pmdp_transfer_prot(mm, addr, &mpmd, hpmdp);
+}
+
/*
* gmap_protect_pmd - set pmd notification bits
* @pmdp: pointer to the pmd to be protected
@@ -1141,7 +1153,8 @@ static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr,
* guest_table_lock held for shadow gmaps.
*/
static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
- pmd_t *pmdp, int prot, unsigned long bits)
+ unsigned long vmaddr, pmd_t *pmdp, pmd_t *hpmdp,
+ int prot, unsigned long bits)
{
int rc;
pte_t *ptep;
@@ -1157,6 +1170,8 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
/* Protect and unlock. */
rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
gmap_pte_op_end(ptl);
+ if (!rc && gmap_pmd_is_split(pmdp))
+ gmap_pte_transfer_prot(gmap->mm, vmaddr, ptep, hpmdp);
return rc;
}
@@ -1178,17 +1193,25 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
unsigned long len, int prot, unsigned long bits)
{
+ spinlock_t *ptl;
unsigned long vmaddr;
- pmd_t *pmdp;
+ pmd_t *pmdp, *hpmdp;
int rc;
while (len) {
rc = -EAGAIN;
+ vmaddr = __gmap_translate(gmap, gaddr);
+ hpmdp = (pmd_t *)huge_pte_offset(gmap->mm, vmaddr, HPAGE_SIZE);
+ if (!hpmdp)
+ BUG();
+ /* Do we need tests here? */
+ ptl = pmd_lock(gmap->mm, hpmdp);
+
pmdp = gmap_pmd_op_walk(gmap, gaddr);
if (pmdp && !(pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)) {
if (!pmd_large(*pmdp)) {
- rc = gmap_protect_pte(gmap, gaddr, pmdp, prot,
- bits);
+ rc = gmap_protect_pte(gmap, gaddr, vmaddr,
+ pmdp, hpmdp, prot, bits);
if (!rc) {
len -= PAGE_SIZE;
gaddr += PAGE_SIZE;
@@ -1200,6 +1223,7 @@ static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
}
gmap_pmd_op_end(gmap, pmdp);
}
+ spin_unlock(ptl);
if (rc && rc != -EFAULT) {
vmaddr = __gmap_translate(gmap, gaddr);
if (IS_ERR_VALUE(vmaddr))
@@ -1268,7 +1292,7 @@ int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val,
pmdp = gmap_pmd_op_walk(gmap, gaddr);
if (pmdp && !(pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)) {
if (!pmd_large(*pmdp)) {
- ptep = pte_alloc_map_lock(gmap->mm, pmdp, gaddr, &ptl);
+ ptep = gmap_pte_from_pmd(gmap, pmdp, gaddr, &ptl);
if (ptep) {
pte = *ptep;
if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
@@ -1331,6 +1355,28 @@ static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
}
}
+static int gmap_protect_rmap_pte(struct gmap *sg, struct gmap_rmap *rmap,
+ unsigned long paddr, unsigned long vmaddr,
+ pmd_t *pmdp, pmd_t *hpmdp, int prot)
+{
+ int rc = 0;
+ pte_t *ptep = NULL;
+ spinlock_t *ptl = NULL;
+
+ ptep = gmap_pte_from_pmd(sg->parent, pmdp, paddr, &ptl);
+ if (unlikely(!ptep))
+ return -ENOMEM;
+
+ spin_lock(&sg->guest_table_lock);
+ rc = gmap_protect_pte(sg->parent, paddr, vmaddr, pmdp, hpmdp,
+ prot, GMAP_NOTIFY_SHADOW);
+ if (!rc)
+ gmap_insert_rmap(sg, vmaddr, rmap);
+ spin_unlock(&sg->guest_table_lock);
+ gmap_pte_op_end(ptl);
+ return rc;
+}
+
/**
* gmap_protect_rmap - modify access rights to memory and create an rmap
* @sg: pointer to the shadow guest address space structure
@@ -1348,8 +1394,8 @@ static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
struct gmap *parent;
struct gmap_rmap *rmap;
unsigned long vmaddr;
+ pmd_t *pmdp, *hpmdp;
spinlock_t *ptl;
- pte_t *ptep;
int rc;
BUG_ON(!gmap_is_shadow(sg));
@@ -1358,36 +1404,47 @@ static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
vmaddr = __gmap_translate(parent, paddr);
if (IS_ERR_VALUE(vmaddr))
return vmaddr;
+ hpmdp = (pmd_t *)huge_pte_offset(parent->mm, vmaddr, HPAGE_SIZE);
+ ptl = pmd_lock(parent->mm, hpmdp);
rmap = kzalloc(sizeof(*rmap), GFP_KERNEL);
- if (!rmap)
+ if (!rmap) {
+ spin_unlock(ptl);
return -ENOMEM;
+ }
rmap->raddr = raddr;
rc = radix_tree_preload(GFP_KERNEL);
if (rc) {
+ spin_unlock(ptl);
kfree(rmap);
return rc;
}
rc = -EAGAIN;
- ptep = gmap_pte_op_walk(parent, paddr, &ptl);
- if (ptep) {
- spin_lock(&sg->guest_table_lock);
- rc = ptep_force_prot(parent->mm, paddr, ptep, prot,
- GMAP_NOTIFY_SHADOW);
- if (!rc)
- gmap_insert_rmap(sg, vmaddr, rmap);
- spin_unlock(&sg->guest_table_lock);
- gmap_pte_op_end(ptl);
+ pmdp = gmap_pmd_op_walk(parent, paddr);
+ if (pmdp && !(pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)) {
+ if (!pmd_large(*pmdp)) {
+ rc = gmap_protect_rmap_pte(sg, rmap, paddr,
+ vmaddr, pmdp, hpmdp,
+ prot);
+ if (!rc) {
+ paddr += PAGE_SIZE;
+ len -= PAGE_SIZE;
+ }
+ } else {
+ rc = gmap_pmd_split(parent, paddr, pmdp);
+ if (!rc)
+ rc = -EFAULT;
+ }
+ gmap_pmd_op_end(parent, pmdp);
}
+ spin_unlock(ptl);
radix_tree_preload_end();
- if (rc) {
+ if (rc)
kfree(rmap);
+ if (rc == -EAGAIN) {
rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
if (rc)
return rc;
- continue;
}
- paddr += PAGE_SIZE;
- len -= PAGE_SIZE;
}
return 0;
}
--
2.7.4
