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Subject[PATCH 10/10] KVM: Log ROE violations in system log
Date
Signed-off-by: Ahmed Abd El Mawgood <ahmedsoliman@mena.vt.edu>
---
virt/kvm/kvm_main.c | 5 +++++
virt/kvm/roe.c | 14 ++++++++++++++
virt/kvm/roe_generic.h | 2 +-
3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c3a21d3bc8..661933053f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1870,6 +1870,7 @@ static u64 roe_gfn_to_hva(struct kvm_memory_slot *slot, gfn_t gfn, int offset,
addr = __gfn_to_hva_many(slot, gfn, NULL, false);
return addr;
}
+
static int __kvm_write_guest_page(struct kvm_memory_slot *memslot, gfn_t gfn,
const void *data, int offset, int len)
{
@@ -1877,6 +1878,10 @@ static int __kvm_write_guest_page(struct kvm_memory_slot *memslot, gfn_t gfn,
unsigned long addr;

addr = roe_gfn_to_hva(memslot, gfn, offset, len);
+ if (gfn_is_full_roe(memslot, gfn) ||
+ kvm_roe_check_range(memslot, gfn, offset, len))
+ kvm_warning_roe_violation((gfn << PAGE_SHIFT) + offset, data,
+ len);
if (kvm_is_error_hva(addr))
return -EFAULT;
r = __copy_to_user((void __user *)addr + offset, data, len);
diff --git a/virt/kvm/roe.c b/virt/kvm/roe.c
index 6555838f0c..36b85fb303 100644
--- a/virt/kvm/roe.c
+++ b/virt/kvm/roe.c
@@ -76,6 +76,20 @@ void kvm_roe_free(struct kvm_memory_slot *slot)
kvfree(slot->prot_list);
}

+void kvm_warning_roe_violation(u64 addr, const void *data, int len)
+{
+ int i;
+ const char *d = data;
+ char *buf = kvmalloc(len * 3 + 1, GFP_KERNEL);
+
+ for (i = 0; i < len; i++)
+ sprintf(buf+3*i, " %02x", d[i]);
+ pr_warn("ROE violation:\n");
+ pr_warn("\tAttempt to write %d bytes at address 0x%08llx\n", len, addr);
+ pr_warn("\tData: %s\n", buf);
+ kvfree(buf);
+}
+
static void kvm_roe_protect_slot(struct kvm *kvm, struct kvm_memory_slot *slot,
gfn_t gfn, u64 npages, bool partial)
{
diff --git a/virt/kvm/roe_generic.h b/virt/kvm/roe_generic.h
index f1ce4a8aec..8c191362cd 100644
--- a/virt/kvm/roe_generic.h
+++ b/virt/kvm/roe_generic.h
@@ -14,5 +14,5 @@ void kvm_roe_free(struct kvm_memory_slot *slot);
int kvm_roe_init(struct kvm_memory_slot *slot);
bool kvm_roe_check_range(struct kvm_memory_slot *slot, gfn_t gfn, int offset,
int len);
-
+void kvm_warning_roe_violation(u64 addr, const void *data, int len);
#endif
--
2.19.2
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