x86: Mask X86_FEATURE_XSAVE in cpuid leaf 1, ecx, as we don't allow

guests to use it (by setting cr4.OSXSAVE).

This prevents crashes in pvops kernels, as new versions of Linux
try to use this feature.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
xen-unstable changeset:   19288:9ed53e60211954c2a04dfdcae207819276b2cca0
xen-unstable date:        Mon Mar 09 08:54:19 2009 +0000

diff --git a/tools/libxc/xc_cpufeature.h b/tools/libxc/xc_cpufeature.h
index 047a6c9fc797d1d960ece597da45a3f8dca9a4f1..b5ab901c6846fcba508492d4c87cee497a868074 100644 (file)
--- a/tools/libxc/xc_cpufeature.h
+++ b/tools/libxc/xc_cpufeature.h
@@ -83,6 +83,7 @@
 #define X86_FEATURE_SSE4_1     (4*32+19) /* Streaming SIMD Extensions 4.1 */
 #define X86_FEATURE_SSE4_2     (4*32+20) /* Streaming SIMD Extensions 4.2 */
 #define X86_FEATURE_POPCNT     (4*32+23) /* POPCNT instruction */
+#define X86_FEATURE_XSAVE      (4*32+26) /* XSAVE/XRSTOR/XSETBV/XGETBV */
 #define X86_FEATURE_HYPERVISOR (4*32+31) /* Running under some hypervisor */
 
 /* VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001, word 5 */

diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index 304a414505ffa11dff3d201674cacf4d58645ca3..f4ceddbab6f9eab2b677b52ad04152705173527d 100644 (file)
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -285,6 +285,7 @@ static void xc_cpuid_pv_policy(
         clear_bit(X86_FEATURE_XTPR, regs[2]);
         clear_bit(X86_FEATURE_PDCM, regs[2]);
         clear_bit(X86_FEATURE_DCA, regs[2]);
+        clear_bit(X86_FEATURE_XSAVE, regs[2]);
         set_bit(X86_FEATURE_HYPERVISOR, regs[2]);
         break;
     case 0x80000001:

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index e2722eb6a4e5a4f3771cb322c68256e589ea9e8f..854b55d3a5b08607187a3705a44bcc30f3458a57 100644 (file)
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -742,6 +742,7 @@ static void pv_cpuid(struct cpu_user_regs *regs)
         __clear_bit(X86_FEATURE_XTPR % 32, &c);
         __clear_bit(X86_FEATURE_PDCM % 32, &c);
         __clear_bit(X86_FEATURE_DCA % 32, &c);
+        __clear_bit(X86_FEATURE_XSAVE % 32, &c);
         __set_bit(X86_FEATURE_HYPERVISOR % 32, &c);
         break;
     case 0x80000001:

diff --git a/xen/include/asm-x86/cpufeature.h b/xen/include/asm-x86/cpufeature.h
index 481236c833b8a7b38ab1e37f2ab69877e5e364e8..5e2acab7d8e7fd795cb73a324eb51ea176307bfc 100644 (file)
--- a/xen/include/asm-x86/cpufeature.h
+++ b/xen/include/asm-x86/cpufeature.h
@@ -94,6 +94,7 @@
 #define X86_FEATURE_SSE4_2     (4*32+20) /* Streaming SIMD Extensions 4.2 */
 #define X86_FEATURE_X2APIC     (4*32+21) /* Extended xAPIC */
 #define X86_FEATURE_POPCNT     (4*32+23) /* POPCNT instruction */
+#define X86_FEATURE_XSAVE      (4*32+26) /* XSAVE/XRSTOR/XSETBV/XGETBV */
 #define X86_FEATURE_HYPERVISOR (4*32+31) /* Running under some hypervisor */
 
 /* VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001, word 5 */