Changeset 55318 in vbox

Timestamp:

Apr 17, 2015 8:25:49 AM (10 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

99638

Message:

forward-ported r98913 from 4.3 to trunk (Support/Darwin: on recent CPUs set EFLAGS.AC before executing the IOCtl to disable SMAP)

Location:

trunk

Files:

• . (modified) (1 prop)
• include/iprt/asm-amd64-x86.h (modified) (1 diff)
• src/VBox (modified) (1 prop)
• src/VBox/HostDrivers/Support/darwin/SUPDrv-darwin.cpp (modified) (6 diffs)

trunk/include/iprt/asm-amd64-x86.h

@@ -3093 +3093 @@
 }
 
+
+/*
+ * Clear the AC bit in the EFLAGS register.
+ * Requires the X86_CPUID_STEXT_FEATURE_EBX_SMAP CPUID bit set.
+ * Requires to be executed in R0.
+ */
+DECLINLINE(void) ASMClearAC(void)
+{
+#if RT_INLINE_ASM_GNU_STYLE
+    __asm__ __volatile__ (".byte 0x0f,0x01,0xca\n\t");
+#else
+    __asm
+    {
+        _emit   0x0f
+        _emit   0x01
+        _emit   0xca
+    }
+#endif
+}
+
+
+/*
+ * Set the AC bit in the EFLAGS register.
+ * Requires the X86_CPUID_STEXT_FEATURE_EBX_SMAP CPUID bit set.
+ * Requires to be executed in R0.
+ */
+DECLINLINE(void) ASMSetAC(void)
+{
+#if RT_INLINE_ASM_GNU_STYLE
+    __asm__ __volatile__ (".byte 0x0f,0x01,0xcb\n\t");
+#else
+    __asm
+    {
+        _emit   0x0f
+        _emit   0x01
+        _emit   0xcb
+    }
+#endif
+}
+
 /** @} */
 #endif

trunk/src/VBox/HostDrivers/Support/darwin/SUPDrv-darwin.cpp

@@ -52 +52 @@
 #include <iprt/power.h>
 #include <iprt/dbg.h>
+#include <iprt/x86.h>
 #include <VBox/err.h>
 #include <VBox/log.h>
@@ -105 +106 @@
 static int              VBoxDrvDarwinClose(dev_t Dev, int fFlags, int fDevType, struct proc *pProcess);
 static int              VBoxDrvDarwinIOCtl(dev_t Dev, u_long iCmd, caddr_t pData, int fFlags, struct proc *pProcess);
+static int              VBoxDrvDarwinIOCtlSMAP(dev_t Dev, u_long iCmd, caddr_t pData, int fFlags, struct proc *pProcess);
 static int              VBoxDrvDarwinIOCtlSlow(PSUPDRVSESSION pSession, u_long iCmd, caddr_t pData, struct proc *pProcess);
 
@@ -113 +115 @@
 
 static void             vboxdrvDarwinResolveSymbols(void);
+static bool             vboxdrvDarwinCpuHasSMAP(void);
 
 
@@ -275 +278 @@
             if (RT_SUCCESS(rc))
             {
+                if (vboxdrvDarwinCpuHasSMAP())
+                    g_DevCW.d_ioctl = VBoxDrvDarwinIOCtlSMAP;
                 /*
                  * Registering ourselves as a character device.
@@ -598 +603 @@
 
 /**
+ * Alternative Device I/O Control entry point on hosts with SMAP support.
+ *
+ * @returns Darwin for slow IOCtls and VBox status code for the fast ones.
+ * @param   Dev         The device number (major+minor).
+ * @param   iCmd        The IOCtl command.
+ * @param   pData       Pointer to the data (if any it's a SUPDRVIOCTLDATA (kernel copy)).
+ * @param   fFlags      Flag saying we're a character device (like we didn't know already).
+ * @param   pProcess    The process issuing this request.
+ */
+static int VBoxDrvDarwinIOCtlSMAP(dev_t Dev, u_long iCmd, caddr_t pData, int fFlags, struct proc *pProcess)
+{
+    /*
+     * Allow VBox R0 code to touch R3 memory. Setting the AC bit disables the
+     * SMAP check.
+     */
+    RTCCUINTREG uFlags = ASMGetFlags();
+    ASMSetAC();
+    int rc = VBoxDrvDarwinIOCtl(Dev, iCmd, pData, fFlags, pProcess);
+    ASMSetFlags(uFlags);
+    return rc;
+}
+
+
+/**
  * Worker for VBoxDrvDarwinIOCtl that takes the slow IOCtl functions.
  *
@@ -1286 +1315 @@
 }
 
+/**
+ * Check if the CPU has SMAP support.
+ */
+static bool vboxdrvDarwinCpuHasSMAP(void)
+{
+    uint32_t uMaxId, uEAX, uEBX, uECX, uEDX;
+    ASMCpuId(0, &uMaxId, &uEBX, &uECX, &uEDX);
+    if (   ASMIsValidStdRange(uMaxId)
+        && uMaxId >= 0x00000007)
+    {
+        ASMCpuId_Idx_ECX(0x00000007, 0, &uEAX, &uEBX, &uECX, &uEDX);
+        if (uEBX & X86_CPUID_STEXT_FEATURE_EBX_SMAP)
+            return true;
+    }
+    return false;
+}
 
 RTDECL(int) SUPR0Printf(const char *pszFormat, ...)