Jan Beulich
2011-Feb-10 13:57 UTC
[Xen-devel] [PATCH] x86: tighten conditions under which writing certain MSRs is permitted
MSRs that control physical CPU aspects generally are pointless (and
possibly dangerous) to be written when the writer isn''t sufficiently
aware that it''s running virtualized.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -2282,7 +2282,7 @@ static int emulate_privileged_op(struct
if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD ||
boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 > 0x17 )
goto fail;
- if ( !IS_PRIV(v->domain) )
+ if ( !IS_PRIV(v->domain) || !is_pinned_vcpu(v) )
break;
if ( (rdmsr_safe(MSR_AMD64_NB_CFG, val) != 0) ||
(eax != (uint32_t)val) ||
@@ -2295,7 +2295,7 @@ static int emulate_privileged_op(struct
if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD ||
boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 > 0x17 )
goto fail;
- if ( !IS_PRIV(v->domain) )
+ if ( !IS_PRIV(v->domain) || !is_pinned_vcpu(v) )
break;
if ( (rdmsr_safe(MSR_FAM10H_MMIO_CONF_BASE, val) != 0) )
goto fail;
@@ -2317,6 +2317,8 @@ static int emulate_privileged_op(struct
case MSR_IA32_UCODE_REV:
if ( boot_cpu_data.x86_vendor != X86_VENDOR_INTEL )
goto fail;
+ if ( !IS_PRIV(v->domain) || !is_pinned_vcpu(v) )
+ break;
if ( rdmsr_safe(regs->ecx, val) )
goto fail;
if ( msr_content )
@@ -2324,7 +2326,7 @@ static int emulate_privileged_op(struct
break;
case MSR_IA32_MISC_ENABLE:
if ( rdmsr_safe(regs->ecx, val) )
- goto invalid;
+ goto fail;
val = guest_misc_enable(val);
if ( msr_content != val )
goto invalid;
@@ -2351,7 +2353,7 @@ static int emulate_privileged_op(struct
case MSR_IA32_ENERGY_PERF_BIAS:
if ( boot_cpu_data.x86_vendor != X86_VENDOR_INTEL )
goto fail;
- if ( (v->domain->domain_id != 0) || !is_pinned_vcpu(v) )
+ if ( !IS_PRIV(v->domain) || !is_pinned_vcpu(v) )
break;
if ( wrmsr_safe(regs->ecx, msr_content) != 0 )
goto fail;
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