Jan Beulich
2008-Mar-14 11:28 UTC
[Xen-devel] [PATCH] x86: fix feature availability for PV guests
PV guests should not be allowed to believe features not currently
virtualized (in many cases, requiring special MSRs) are available. Of
course it is bad enough that to work on older hypervisors guests will
still need to special case this, but better fix it now than never.
A question I came across while doing this - why is is_pv_32bit_vcpu()
not simply defined to constant 1 on 32-bits?
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Index: 2008-03-05/xen/arch/x86/traps.c
==================================================================---
2008-03-05.orig/xen/arch/x86/traps.c 2008-03-14 09:17:05.000000000 +0100
+++ 2008-03-05/xen/arch/x86/traps.c 2008-03-14 11:31:36.000000000 +0100
@@ -677,32 +677,75 @@ static int emulate_forced_invalid_op(str
: "=a" (a), "=b" (b), "=c" (c),
"=d" (d)
: "0" (a), "1" (b), "2" (c),
"3" (d) );
- if ( regs->eax == 1 )
+ if ( (regs->eax & 0x7fffffff) == 1 )
{
/* Modify Feature Information. */
__clear_bit(X86_FEATURE_VME, &d);
__clear_bit(X86_FEATURE_PSE, &d);
__clear_bit(X86_FEATURE_PGE, &d);
+ __clear_bit(X86_FEATURE_MCE, &d);
+ __clear_bit(X86_FEATURE_MCA, &d);
+ if ( !IS_PRIV(current->domain) )
+ __clear_bit(X86_FEATURE_MTRR, &d);
+ __clear_bit(X86_FEATURE_PSE36, &d);
+ }
+ switch ( (uint32_t)regs->eax )
+ {
+ case 1:
+ /* Modify Feature Information. */
if ( !cpu_has_sep )
__clear_bit(X86_FEATURE_SEP, &d);
#ifdef __i386__
if ( !supervisor_mode_kernel )
__clear_bit(X86_FEATURE_SEP, &d);
#endif
- if ( !IS_PRIV(current->domain) )
- __clear_bit(X86_FEATURE_MTRR, &d);
- }
- else if ( regs->eax == 0x80000001 )
- {
+ __clear_bit(X86_FEATURE_DS, &d);
+ __clear_bit(X86_FEATURE_ACC, &d);
+ __clear_bit(X86_FEATURE_PBE, &d);
+
+ __clear_bit(X86_FEATURE_DTES64 % 32, &c);
+ __clear_bit(X86_FEATURE_MWAIT % 32, &c);
+ __clear_bit(X86_FEATURE_DSCPL % 32, &c);
+ __clear_bit(X86_FEATURE_VMXE % 32, &c);
+ __clear_bit(X86_FEATURE_SMXE % 32, &c);
+ __clear_bit(X86_FEATURE_EST % 32, &c);
+ __clear_bit(X86_FEATURE_TM2 % 32, &c);
+ if ( is_pv_32bit_vcpu(current) )
+ __clear_bit(X86_FEATURE_CX16 % 32, &c);
+ __clear_bit(X86_FEATURE_XTPR % 32, &c);
+ __clear_bit(X86_FEATURE_PDCM % 32, &c);
+ __clear_bit(X86_FEATURE_DCA % 32, &c);
+ break;
+ case 0x80000001:
/* Modify Feature Information. */
-#ifdef __i386__
- __clear_bit(X86_FEATURE_SYSCALL % 32, &d);
+ if ( is_pv_32bit_vcpu(current) )
+ {
+ __clear_bit(X86_FEATURE_LM % 32, &d);
+ __clear_bit(X86_FEATURE_LAHF_LM % 32, &c);
+ }
+#ifndef __i386__
+ if ( is_pv_32on64_vcpu(current) &&
+ boot_cpu_data.x86_vendor != X86_VENDOR_AMD )
#endif
+ __clear_bit(X86_FEATURE_SYSCALL % 32, &d);
+ __clear_bit(X86_FEATURE_PAGE1GB % 32, &d);
__clear_bit(X86_FEATURE_RDTSCP % 32, &d);
- }
- else
- {
+
+ __clear_bit(X86_FEATURE_SVME % 32, &c);
+ __clear_bit(X86_FEATURE_OSVW % 32, &c);
+ __clear_bit(X86_FEATURE_IBS % 32, &c);
+ __clear_bit(X86_FEATURE_SKINIT % 32, &c);
+ __clear_bit(X86_FEATURE_WDT % 32, &c);
+ break;
+ case 5: /* MONITOR/MWAIT */
+ case 0xa: /* Architectural Performance Monitor Features */
+ case 0x8000000a: /* SVM revision and features */
+ case 0x8000001b: /* Instruction Based Sampling */
+ a = b = c = d = 0;
+ break;
+ default:
(void)cpuid_hypervisor_leaves(regs->eax, &a, &b, &c,
&d);
+ break;
}
regs->eax = a;
@@ -2027,6 +2070,15 @@ static int emulate_privileged_op(struct
if ( rdmsr_safe(regs->ecx, regs->eax, regs->edx) )
goto fail;
break;
+ case MSR_IA32_MISC_ENABLE:
+ if ( rdmsr_safe(regs->ecx, regs->eax, regs->edx) )
+ goto fail;
+ regs->eax &= ~(MSR_IA32_MISC_ENABLE_PERF_AVAIL |
+ MSR_IA32_MISC_ENABLE_MONITOR_ENABLE);
+ regs->eax |= MSR_IA32_MISC_ENABLE_BTS_UNAVAIL |
+ MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL |
+ MSR_IA32_MISC_ENABLE_XTPR_DISABLE;
+ break;
default:
if ( rdmsr_hypervisor_regs(regs->ecx, &l, &h) )
{
Index: 2008-03-05/xen/include/asm-x86/cpufeature.h
==================================================================---
2008-03-05.orig/xen/include/asm-x86/cpufeature.h 2008-03-05 17:55:11.000000000
+0100
+++ 2008-03-05/xen/include/asm-x86/cpufeature.h 2008-03-14 09:50:21.000000000
+0100
@@ -42,6 +42,7 @@
#define X86_FEATURE_HT (0*32+28) /* Hyper-Threading */
#define X86_FEATURE_ACC (0*32+29) /* Automatic clock control */
#define X86_FEATURE_IA64 (0*32+30) /* IA-64 processor */
+#define X86_FEATURE_PBE (0*32+31) /* Pending Break Enable */
/* AMD-defined CPU features, CPUID level 0x80000001, word 1 */
/* Don''t duplicate feature flags which are redundant with Intel! */
@@ -76,6 +77,7 @@
/* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
#define X86_FEATURE_XMM3 (4*32+ 0) /* Streaming SIMD Extensions-3 */
+#define X86_FEATURE_DTES64 (4*32+ 2) /* 64-bit Debug Store */
#define X86_FEATURE_MWAIT (4*32+ 3) /* Monitor/Mwait support */
#define X86_FEATURE_DSCPL (4*32+ 4) /* CPL Qualified Debug Store */
#define X86_FEATURE_VMXE (4*32+ 5) /* Virtual Machine Extensions */
@@ -115,6 +117,8 @@
#define X86_FEATURE_MISALIGNSSE (6*32+ 7) /* Misaligned SSE Access */
#define X86_FEATURE_3DNOWPF (6*32+ 8) /* 3DNow! Prefetch */
#define X86_FEATURE_OSVW (6*32+ 9) /* OS Visible Workaround */
+#define X86_FEATURE_IBS (6*32+ 10) /* Instruction Based Sampling */
+#define X86_FEATURE_SSE5 (6*32+ 11) /* AMD Streaming SIMD Extensions-5 */
#define X86_FEATURE_SKINIT (6*32+ 12) /* SKINIT, STGI/CLGI, DEV */
#define X86_FEATURE_WDT (6*32+ 13) /* Watchdog Timer */
Index: 2008-03-05/xen/include/asm-x86/msr-index.h
==================================================================---
2008-03-05.orig/xen/include/asm-x86/msr-index.h 2007-11-12 08:47:43.000000000
+0100
+++ 2008-03-05/xen/include/asm-x86/msr-index.h 2008-03-14 10:40:08.000000000
+0100
@@ -255,6 +255,8 @@
#define MSR_IA32_MISC_ENABLE_PERF_AVAIL (1<<7)
#define MSR_IA32_MISC_ENABLE_BTS_UNAVAIL (1<<11)
#define MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL (1<<12)
+#define MSR_IA32_MISC_ENABLE_MONITOR_ENABLE (1<<18)
+#define MSR_IA32_MISC_ENABLE_XTPR_DISABLE (1<<23)
/* Intel Model 6 */
#define MSR_P6_EVNTSEL0 0x00000186
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Keir Fraser
2008-Mar-14 11:33 UTC
Re: [Xen-devel] [PATCH] x86: fix feature availability for PV guests
On 14/3/08 11:28, "Jan Beulich" <jbeulich@novell.com> wrote:> PV guests should not be allowed to believe features not currently > virtualized (in many cases, requiring special MSRs) are available. Of > course it is bad enough that to work on older hypervisors guests will > still need to special case this, but better fix it now than never.IMO we should whitelist the features just as we now do for HVM guests. We already have that code; although we probably cannot easily share it with the PV code, it probably only needs copying-and-tweaking.> A question I came across while doing this - why is is_pv_32bit_vcpu() > not simply defined to constant 1 on 32-bits?Because it is occasionally applied to HVM guests. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel