Changeset 26947 in vbox for trunk/src/VBox

Timestamp:

Mar 2, 2010 2:11:43 PM (15 years ago)

Author:

vboxsync

Message:

Avoid deadlocks in PGMR3PhysFreeRamPages

Location:

trunk/src/VBox/VMM

Files:

• PGMInternal.h (modified) (1 diff)
• PGMPhys.cpp (modified) (3 diffs)

trunk/src/VBox/VMM/PGMInternal.h

@@ -841 +841 @@
 /** Can use a page directory entry to map the continous range. */
 #define PGM_PAGE_PDE_TYPE_PDE                  2
+/** Can use a page directory entry to map the continous range - temporarily disabled (by page monitoring). */
+#define PGM_PAGE_PDE_TYPE_PDE_DISABLED         3
 /** @} */
 

trunk/src/VBox/VMM/PGMPhys.cpp

@@ -839 +839 @@
 
 /**
- * Frees a range of ram pages, replacing them with ZERO pages
+ * Frees a range of ram pages, replacing them with ZERO pages; helper for PGMR3PhysFreeRamPages
  *
  * @returns VBox status code.
@@ -846 +846 @@
  * @param   paPhysPage  Array of guest physical addresses
  */
-VMMR3DECL(int) PGMR3PhysFreeRamPages(PVM pVM, unsigned cPages, RTGCPHYS *paPhysPage)
+static DECLCALLBACK(void) pgmR3PhysFreeRamPagesHelper(PVM pVM, unsigned cPages, RTGCPHYS *paPhysPage)
 {
     uintptr_t paUser[2];
@@ -854 +854 @@
     int rc = VMMR3EmtRendezvous(pVM, VMMEMTRENDEZVOUS_FLAGS_TYPE_ONCE, pgmR3PhysFreeRamPagesRendezvous, (void *)paUser);
     AssertRC(rc);
+
+    /* Made a copy in PGMR3PhysFreeRamPages; free it here. */
+    RTMemFree(paPhysPage);
+}
+
+/**
+ * Frees a range of ram pages, replacing them with ZERO pages
+ *
+ * @returns VBox status code.
+ * @param   pVM         The VM handle.
+ * @param   cPages      Number of pages to free
+ * @param   paPhysPage  Array of guest physical addresses
+ */
+VMMR3DECL(int) PGMR3PhysFreeRamPages(PVM pVM, unsigned cPages, RTGCPHYS *paPhysPage)
+{
+    int rc;
+
+    /* Currently only used by the VMM device in responds to a balloon request. */
+    if (pVM->cCpus > 1)
+    {
+        unsigned cbPhysPage = cPages * sizeof(paPhysPage[0]);
+        RTGCPHYS *paPhysPageCopy = (RTGCPHYS *)RTMemAlloc(cbPhysPage);
+        AssertReturn(paPhysPageCopy, VERR_NO_MEMORY);
+
+        memcpy(paPhysPageCopy, paPhysPage, cbPhysPage);
+
+        /* We own the IOM lock here and could cause a deadlock by waiting for another VCPU that is blocking on the IOM lock. */
+        rc = VMR3ReqCallNoWait(pVM, VMCPUID_ANY_QUEUE, (PFNRT)pgmR3PhysFreeRamPagesHelper, 3, pVM, cPages, paPhysPageCopy);
+        AssertRC(rc);
+    }
+    else
+    {
+        uintptr_t paUser[2];
+
+        paUser[0] = cPages;
+        paUser[1] = (uintptr_t)paPhysPage;
+        rc = VMMR3EmtRendezvous(pVM, VMMEMTRENDEZVOUS_FLAGS_TYPE_ONCE, pgmR3PhysFreeRamPagesRendezvous, (void *)paUser);
+        AssertRC(rc);
+    }
     return rc;
 }
+
 
 /**