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>

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 d75fe2b013aea796039d106b2aa0e4fe2e24e56d..f9ef0de10b3574e06d1258f22378b61a1c22d887 100644 (file)
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -311,6 +311,7 @@ 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 84f09c6c76525d9006fa26de02c9c2b983a452d4..1f246c950b713fe2f1158164fddd546b0fc726f1 100644 (file)
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -757,6 +757,7 @@ 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);
         if ( !cpu_has_apic )
            __clear_bit(X86_FEATURE_X2APIC % 32, &c);
         __set_bit(X86_FEATURE_HYPERVISOR % 32, &c);

diff --git a/xen/include/asm-x86/cpufeature.h b/xen/include/asm-x86/cpufeature.h
index 7df04869819067c69aabda7cb41fbb5de90bfdb9..4c6eeabc55dc1f4e46896ce584fed972fd7d1cc2 100644 (file)
--- a/xen/include/asm-x86/cpufeature.h
+++ b/xen/include/asm-x86/cpufeature.h
@@ -95,6 +95,7 @@
 #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 */