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Diffstat (limited to 'arch/s390/kvm/gaccess.c')
-rw-r--r--arch/s390/kvm/gaccess.c69
1 files changed, 56 insertions, 13 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index a688351f4ab5..21c2e61fece4 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -18,6 +18,8 @@
#include "kvm-s390.h"
#include "gaccess.h"
+#define GMAP_SHADOW_FAKE_TABLE 1ULL
+
/*
* vaddress union in order to easily decode a virtual address into its
* region first index, region second index etc. parts.
@@ -129,8 +131,8 @@ static void ipte_lock_simple(struct kvm *kvm)
retry:
read_lock(&kvm->arch.sca_lock);
ic = kvm_s390_get_ipte_control(kvm);
+ old = READ_ONCE(*ic);
do {
- old = READ_ONCE(*ic);
if (old.k) {
read_unlock(&kvm->arch.sca_lock);
cond_resched();
@@ -138,7 +140,7 @@ retry:
}
new = old;
new.k = 1;
- } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+ } while (!try_cmpxchg(&ic->val, &old.val, new.val));
read_unlock(&kvm->arch.sca_lock);
out:
mutex_unlock(&kvm->arch.ipte_mutex);
@@ -154,11 +156,11 @@ static void ipte_unlock_simple(struct kvm *kvm)
goto out;
read_lock(&kvm->arch.sca_lock);
ic = kvm_s390_get_ipte_control(kvm);
+ old = READ_ONCE(*ic);
do {
- old = READ_ONCE(*ic);
new = old;
new.k = 0;
- } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+ } while (!try_cmpxchg(&ic->val, &old.val, new.val));
read_unlock(&kvm->arch.sca_lock);
wake_up(&kvm->arch.ipte_wq);
out:
@@ -172,8 +174,8 @@ static void ipte_lock_siif(struct kvm *kvm)
retry:
read_lock(&kvm->arch.sca_lock);
ic = kvm_s390_get_ipte_control(kvm);
+ old = READ_ONCE(*ic);
do {
- old = READ_ONCE(*ic);
if (old.kg) {
read_unlock(&kvm->arch.sca_lock);
cond_resched();
@@ -182,7 +184,7 @@ retry:
new = old;
new.k = 1;
new.kh++;
- } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+ } while (!try_cmpxchg(&ic->val, &old.val, new.val));
read_unlock(&kvm->arch.sca_lock);
}
@@ -192,13 +194,13 @@ static void ipte_unlock_siif(struct kvm *kvm)
read_lock(&kvm->arch.sca_lock);
ic = kvm_s390_get_ipte_control(kvm);
+ old = READ_ONCE(*ic);
do {
- old = READ_ONCE(*ic);
new = old;
new.kh--;
if (!new.kh)
new.k = 0;
- } while (cmpxchg(&ic->val, old.val, new.val) != old.val);
+ } while (!try_cmpxchg(&ic->val, &old.val, new.val));
read_unlock(&kvm->arch.sca_lock);
if (!new.kh)
wake_up(&kvm->arch.ipte_wq);
@@ -317,7 +319,7 @@ enum prot_type {
PROT_TYPE_DAT = 3,
PROT_TYPE_IEP = 4,
/* Dummy value for passing an initialized value when code != PGM_PROTECTION */
- PROT_NONE,
+ PROT_TYPE_DUMMY,
};
static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar,
@@ -333,7 +335,7 @@ static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva,
switch (code) {
case PGM_PROTECTION:
switch (prot) {
- case PROT_NONE:
+ case PROT_TYPE_DUMMY:
/* We should never get here, acts like termination */
WARN_ON_ONCE(1);
break;
@@ -803,7 +805,7 @@ static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
gpa = kvm_s390_real_to_abs(vcpu, ga);
if (!kvm_is_gpa_in_memslot(vcpu->kvm, gpa)) {
rc = PGM_ADDRESSING;
- prot = PROT_NONE;
+ prot = PROT_TYPE_DUMMY;
}
}
if (rc)
@@ -961,7 +963,7 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
if (rc == PGM_PROTECTION)
prot = PROT_TYPE_KEYC;
else
- prot = PROT_NONE;
+ prot = PROT_TYPE_DUMMY;
rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate);
}
out_unlock:
@@ -1393,6 +1395,44 @@ shadow_pgt:
}
/**
+ * shadow_pgt_lookup() - find a shadow page table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: the address in the shadow aguest address space
+ * @pgt: parent gmap address of the page table to get shadowed
+ * @dat_protection: if the pgtable is marked as protected by dat
+ * @fake: pgt references contiguous guest memory block, not a pgtable
+ *
+ * Returns 0 if the shadow page table was found and -EAGAIN if the page
+ * table was not found.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+static int shadow_pgt_lookup(struct gmap *sg, unsigned long saddr, unsigned long *pgt,
+ int *dat_protection, int *fake)
+{
+ unsigned long pt_index;
+ unsigned long *table;
+ struct page *page;
+ int rc;
+
+ spin_lock(&sg->guest_table_lock);
+ table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
+ if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
+ /* Shadow page tables are full pages (pte+pgste) */
+ page = pfn_to_page(*table >> PAGE_SHIFT);
+ pt_index = gmap_pgste_get_pgt_addr(page_to_virt(page));
+ *pgt = pt_index & ~GMAP_SHADOW_FAKE_TABLE;
+ *dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
+ *fake = !!(pt_index & GMAP_SHADOW_FAKE_TABLE);
+ rc = 0;
+ } else {
+ rc = -EAGAIN;
+ }
+ spin_unlock(&sg->guest_table_lock);
+ return rc;
+}
+
+/**
* kvm_s390_shadow_fault - handle fault on a shadow page table
* @vcpu: virtual cpu
* @sg: pointer to the shadow guest address space structure
@@ -1415,6 +1455,9 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
int dat_protection, fake;
int rc;
+ if (KVM_BUG_ON(!gmap_is_shadow(sg), vcpu->kvm))
+ return -EFAULT;
+
mmap_read_lock(sg->mm);
/*
* We don't want any guest-2 tables to change - so the parent
@@ -1423,7 +1466,7 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,
*/
ipte_lock(vcpu->kvm);
- rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
+ rc = shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection, &fake);
if (rc)
rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection,
&fake);
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-29 02:10:00 +0300