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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] vMCE vs migration
>>> On 26.01.12 at 17:54, George Dunlap <george.dunlap@xxxxxxxxxx> wrote:
> On Tue, 2012-01-24 at 11:08 +0000, Jan Beulich wrote:
>> >>> On 24.01.12 at 11:29, George Dunlap <George.Dunlap@xxxxxxxxxxxxx> wrote:
>> > On Mon, Jan 23, 2012 at 11:08 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>> >> x86's vMCE implementation lets a guest know of as many MCE reporting
>> >> banks as there are in the host. While a PV guest could be expected to
>> >> deal with this number changing (particularly decreasing) during migration
>> >> (not currently handled anywhere afaict), for HVM guests this is certainly
>> >> wrong.
>> >>
>> >> At least to me it isn't, however, clear how to properly handle this. The
>> >> easiest would appear to be to save and restore the number of banks
>> >> the guest was made believe it can access, making vmce_{rd,wr}msr()
>> >> silently tolerate accesses between the host and guest values.
>> >
>> > We ran into this in the XS 6.0 release as well. I think that the
>> > ideal thing to do would be to have a parameter that can be set at
>> > boot, to say how many vMCE banks a guest has, defaulting to the number
>> > of MCE banks on the host. This parameter would be preserved across
>> > migration. Ideally, a pool-aware toolstack like xapi would then set
>> > this value to be the value of the host in the pool with the largest
>> > number of banks, allowing a guest to access all the banks on any host
>> > to which it migrates.
>> >
>> > What do you think?
>>
>> That sounds like the way to go.
>
> So should we put this on IanC's to-do-be-done list? Are you going to
> put it on your to-do list? :-)
Below/attached a draft patch (compile tested only), handling save/
restore of the bank count, but not allowing for a config setting to
specify its initial value (yet).
Jan
--- a/tools/libxc/xc_domain_save.c
+++ b/tools/libxc/xc_domain_save.c
@@ -1879,6 +1879,7 @@ int xc_domain_save(xc_interface *xch, in
domctl.cmd = XEN_DOMCTL_get_ext_vcpucontext;
domctl.domain = dom;
+ memset(&domctl.u, 0, sizeof(domctl.u));
domctl.u.ext_vcpucontext.vcpu = i;
if ( xc_domctl(xch, &domctl) < 0 )
{
--- a/tools/misc/xen-hvmctx.c
+++ b/tools/misc/xen-hvmctx.c
@@ -383,6 +383,13 @@ static void dump_viridian_vcpu(void)
(unsigned long long) p.apic_assist);
}
+static void dump_vmce_vcpu(void)
+{
+ HVM_SAVE_TYPE(VMCE_VCPU) p;
+ READ(p);
+ printf(" VMCE_VCPU: nr_banks %u\n", p.nr_banks);
+}
+
int main(int argc, char **argv)
{
int entry, domid;
@@ -449,6 +456,7 @@ int main(int argc, char **argv)
case HVM_SAVE_CODE(MTRR): dump_mtrr(); break;
case HVM_SAVE_CODE(VIRIDIAN_DOMAIN): dump_viridian_domain(); break;
case HVM_SAVE_CODE(VIRIDIAN_VCPU): dump_viridian_vcpu(); break;
+ case HVM_SAVE_CODE(VMCE_VCPU): dump_vmce_vcpu(); break;
case HVM_SAVE_CODE(END): break;
default:
printf(" ** Don't understand type %u: skipping\n",
--- a/xen/arch/x86/cpu/mcheck/mce.h
+++ b/xen/arch/x86/cpu/mcheck/mce.h
@@ -3,6 +3,7 @@
#define _MCE_H
#include <xen/init.h>
+#include <xen/sched.h>
#include <xen/smp.h>
#include <asm/types.h>
#include <asm/traps.h>
@@ -54,8 +55,8 @@ int unmmap_broken_page(struct domain *d,
u64 mce_cap_init(void);
extern int firstbank;
-int intel_mce_rdmsr(uint32_t msr, uint64_t *val);
-int intel_mce_wrmsr(uint32_t msr, uint64_t val);
+int intel_mce_rdmsr(const struct vcpu *, uint32_t msr, uint64_t *val);
+int intel_mce_wrmsr(struct vcpu *, uint32_t msr, uint64_t val);
struct mcinfo_extended *intel_get_extended_msrs(
struct mcinfo_global *mig, struct mc_info *mi);
@@ -171,18 +172,20 @@ int vmce_domain_inject(struct mcinfo_ban
extern int vmce_init(struct cpuinfo_x86 *c);
-static inline int mce_vendor_bank_msr(uint32_t msr)
+static inline int mce_vendor_bank_msr(const struct vcpu *v, uint32_t msr)
{
if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
- msr >= MSR_IA32_MC0_CTL2 && msr < (MSR_IA32_MC0_CTL2 + nr_mce_banks) )
+ msr >= MSR_IA32_MC0_CTL2 &&
+ msr < MSR_IA32_MCx_CTL2(v->arch.nr_vmce_banks) )
return 1;
return 0;
}
-static inline int mce_bank_msr(uint32_t msr)
+static inline int mce_bank_msr(const struct vcpu *v, uint32_t msr)
{
- if ( (msr >= MSR_IA32_MC0_CTL && msr < MSR_IA32_MCx_CTL(nr_mce_banks)) ||
- mce_vendor_bank_msr(msr) )
+ if ( (msr >= MSR_IA32_MC0_CTL &&
+ msr < MSR_IA32_MCx_CTL(v->arch.nr_vmce_banks)) ||
+ mce_vendor_bank_msr(v, msr) )
return 1;
return 0;
}
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c
@@ -1421,11 +1421,12 @@ enum mcheck_type intel_mcheck_init(struc
}
/* intel specific MCA MSR */
-int intel_mce_wrmsr(uint32_t msr, uint64_t val)
+int intel_mce_wrmsr(struct vcpu *v, uint32_t msr, uint64_t val)
{
int ret = 0;
- if (msr >= MSR_IA32_MC0_CTL2 && msr < (MSR_IA32_MC0_CTL2 + nr_mce_banks))
+ if ( msr >= MSR_IA32_MC0_CTL2 &&
+ msr < MSR_IA32_MCx_CTL2(v->arch.nr_vmce_banks) )
{
mce_printk(MCE_QUIET, "We have disabled CMCI capability, "
"Guest should not write this MSR!\n");
@@ -1435,11 +1436,12 @@ int intel_mce_wrmsr(uint32_t msr, uint64
return ret;
}
-int intel_mce_rdmsr(uint32_t msr, uint64_t *val)
+int intel_mce_rdmsr(const struct vcpu *v, uint32_t msr, uint64_t *val)
{
int ret = 0;
- if (msr >= MSR_IA32_MC0_CTL2 && msr < (MSR_IA32_MC0_CTL2 + nr_mce_banks))
+ if ( msr >= MSR_IA32_MC0_CTL2 &&
+ msr < MSR_IA32_MCx_CTL2(v->arch.nr_vmce_banks) )
{
mce_printk(MCE_QUIET, "We have disabled CMCI capability, "
"Guest should not read this MSR!\n");
--- a/xen/arch/x86/cpu/mcheck/vmce.c
+++ b/xen/arch/x86/cpu/mcheck/vmce.c
@@ -10,6 +10,7 @@
#include <xen/delay.h>
#include <xen/smp.h>
#include <xen/mm.h>
+#include <xen/hvm/save.h>
#include <asm/processor.h>
#include <public/sysctl.h>
#include <asm/system.h>
@@ -61,21 +62,26 @@ void vmce_destroy_msr(struct domain *d)
dom_vmce(d) = NULL;
}
-static int bank_mce_rdmsr(struct domain *d, uint32_t msr, uint64_t *val)
+void vmce_init_vcpu(struct vcpu *v)
{
- int bank, ret = 1;
- struct domain_mca_msrs *vmce = dom_vmce(d);
+ v->arch.nr_vmce_banks = nr_mce_banks;
+}
+
+static int bank_mce_rdmsr(const struct vcpu *v, uint32_t msr, uint64_t *val)
+{
+ int ret = 1;
+ unsigned int bank = (msr - MSR_IA32_MC0_CTL) / 4;
+ struct domain_mca_msrs *vmce = dom_vmce(v->domain);
struct bank_entry *entry;
- bank = (msr - MSR_IA32_MC0_CTL) / 4;
- if ( bank >= nr_mce_banks )
- return -1;
+ *val = 0;
switch ( msr & (MSR_IA32_MC0_CTL | 3) )
{
case MSR_IA32_MC0_CTL:
- *val = vmce->mci_ctl[bank] &
- (h_mci_ctrl ? h_mci_ctrl[bank] : ~0UL);
+ if ( bank < nr_mce_banks )
+ *val = vmce->mci_ctl[bank] &
+ (h_mci_ctrl ? h_mci_ctrl[bank] : ~0UL);
mce_printk(MCE_VERBOSE, "MCE: rdmsr MC%u_CTL 0x%"PRIx64"\n",
bank, *val);
break;
@@ -126,7 +132,7 @@ static int bank_mce_rdmsr(struct domain
switch ( boot_cpu_data.x86_vendor )
{
case X86_VENDOR_INTEL:
- ret = intel_mce_rdmsr(msr, val);
+ ret = intel_mce_rdmsr(v, msr, val);
break;
default:
ret = 0;
@@ -145,13 +151,13 @@ static int bank_mce_rdmsr(struct domain
*/
int vmce_rdmsr(uint32_t msr, uint64_t *val)
{
- struct domain *d = current->domain;
- struct domain_mca_msrs *vmce = dom_vmce(d);
+ const struct vcpu *cur = current;
+ struct domain_mca_msrs *vmce = dom_vmce(cur->domain);
int ret = 1;
*val = 0;
- spin_lock(&dom_vmce(d)->lock);
+ spin_lock(&vmce->lock);
switch ( msr )
{
@@ -173,28 +179,26 @@ int vmce_rdmsr(uint32_t msr, uint64_t *v
*val);
break;
default:
- ret = mce_bank_msr(msr) ? bank_mce_rdmsr(d, msr, val) : 0;
+ ret = mce_bank_msr(cur, msr) ? bank_mce_rdmsr(cur, msr, val) : 0;
break;
}
- spin_unlock(&dom_vmce(d)->lock);
+ spin_unlock(&vmce->lock);
return ret;
}
-static int bank_mce_wrmsr(struct domain *d, u32 msr, u64 val)
+static int bank_mce_wrmsr(struct vcpu *v, u32 msr, u64 val)
{
- int bank, ret = 1;
- struct domain_mca_msrs *vmce = dom_vmce(d);
+ int ret = 1;
+ unsigned int bank = (msr - MSR_IA32_MC0_CTL) / 4;
+ struct domain_mca_msrs *vmce = dom_vmce(v->domain);
struct bank_entry *entry = NULL;
- bank = (msr - MSR_IA32_MC0_CTL) / 4;
- if ( bank >= nr_mce_banks )
- return -EINVAL;
-
switch ( msr & (MSR_IA32_MC0_CTL | 3) )
{
case MSR_IA32_MC0_CTL:
- vmce->mci_ctl[bank] = val;
+ if ( bank < nr_mce_banks )
+ vmce->mci_ctl[bank] = val;
break;
case MSR_IA32_MC0_STATUS:
/* Give the first entry of the list, it corresponds to current
@@ -202,9 +206,9 @@ static int bank_mce_wrmsr(struct domain
* the guest, this node will be deleted.
* Only error bank is written. Non-error banks simply return.
*/
- if ( !list_empty(&dom_vmce(d)->impact_header) )
+ if ( !list_empty(&vmce->impact_header) )
{
- entry = list_entry(dom_vmce(d)->impact_header.next,
+ entry = list_entry(vmce->impact_header.next,
struct bank_entry, list);
if ( entry->bank == bank )
entry->mci_status = val;
@@ -228,7 +232,7 @@ static int bank_mce_wrmsr(struct domain
switch ( boot_cpu_data.x86_vendor )
{
case X86_VENDOR_INTEL:
- ret = intel_mce_wrmsr(msr, val);
+ ret = intel_mce_wrmsr(v, msr, val);
break;
default:
ret = 0;
@@ -247,9 +251,9 @@ static int bank_mce_wrmsr(struct domain
*/
int vmce_wrmsr(u32 msr, u64 val)
{
- struct domain *d = current->domain;
+ struct vcpu *cur = current;
struct bank_entry *entry = NULL;
- struct domain_mca_msrs *vmce = dom_vmce(d);
+ struct domain_mca_msrs *vmce = dom_vmce(cur->domain);
int ret = 1;
if ( !g_mcg_cap )
@@ -266,7 +270,7 @@ int vmce_wrmsr(u32 msr, u64 val)
vmce->mcg_status = val;
mce_printk(MCE_VERBOSE, "MCE: wrmsr MCG_STATUS %"PRIx64"\n", val);
/* For HVM guest, this is the point for deleting vMCE injection node */
- if ( d->is_hvm && (vmce->nr_injection > 0) )
+ if ( is_hvm_vcpu(cur) && (vmce->nr_injection > 0) )
{
vmce->nr_injection--; /* Should be 0 */
if ( !list_empty(&vmce->impact_header) )
@@ -293,7 +297,7 @@ int vmce_wrmsr(u32 msr, u64 val)
ret = -1;
break;
default:
- ret = mce_bank_msr(msr) ? bank_mce_wrmsr(d, msr, val) : 0;
+ ret = mce_bank_msr(cur, msr) ? bank_mce_wrmsr(cur, msr, val) : 0;
break;
}
@@ -301,6 +305,47 @@ int vmce_wrmsr(u32 msr, u64 val)
return ret;
}
+static int vmce_save_vcpu_ctxt(struct domain *d, hvm_domain_context_t *h)
+{
+ struct vcpu *v;
+ int err = 0;
+
+ for_each_vcpu( d, v ) {
+ struct hvm_vmce_vcpu ctxt = {
+ .nr_banks = v->arch.nr_vmce_banks
+ };
+
+ err = hvm_save_entry(VMCE_VCPU, v->vcpu_id, h, &ctxt);
+ if ( err )
+ break;
+ }
+
+ return err;
+}
+
+static int vmce_load_vcpu_ctxt(struct domain *d, hvm_domain_context_t *h)
+{
+ unsigned int vcpuid = hvm_load_instance(h);
+ struct vcpu *v;
+ struct hvm_vmce_vcpu ctxt;
+ int err;
+
+ if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) == NULL )
+ {
+ gdprintk(XENLOG_ERR, "HVM restore: domain has no vcpu %u\n", vcpuid);
+ return -EINVAL;
+ }
+
+ err = hvm_load_entry(VMCE_VCPU, h, &ctxt);
+ if ( !err )
+ v->arch.nr_vmce_banks = ctxt.nr_banks;
+
+ return err;
+}
+
+HVM_REGISTER_SAVE_RESTORE(VMCE_VCPU, vmce_save_vcpu_ctxt,
+ vmce_load_vcpu_ctxt, 1, HVMSR_PER_VCPU);
+
int inject_vmce(struct domain *d)
{
int cpu = smp_processor_id();
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -468,6 +468,8 @@ int vcpu_initialise(struct vcpu *v)
v->arch.pv_vcpu.ctrlreg[4] = real_cr4_to_pv_guest_cr4(mmu_cr4_features);
+ vmce_init_vcpu(v);
+
rc = is_pv_32on64_vcpu(v) ? setup_compat_l4(v) : 0;
done:
if ( rc )
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1027,11 +1027,12 @@ long arch_do_domctl(
evc->syscall32_callback_eip = 0;
evc->syscall32_disables_events = 0;
}
+ evc->nr_mce_banks = v->arch.nr_vmce_banks;
}
else
{
ret = -EINVAL;
- if ( evc->size != sizeof(*evc) )
+ if ( evc->size < offsetof(typeof(*evc), nr_mce_banks) )
goto ext_vcpucontext_out;
#ifdef __x86_64__
if ( !is_hvm_domain(d) )
@@ -1059,6 +1060,16 @@ long arch_do_domctl(
(evc->syscall32_callback_cs & ~3) ||
evc->syscall32_callback_eip )
goto ext_vcpucontext_out;
+
+ if ( evc->size >= offsetof(typeof(*evc),
mbz[ARRAY_SIZE(evc->mbz)]) )
+ {
+ unsigned int i;
+
+ for ( i = 0; i < ARRAY_SIZE(evc->mbz); ++i )
+ if ( evc->mbz[i] )
+ goto ext_vcpucontext_out;
+ v->arch.nr_vmce_banks = evc->nr_mce_banks;
+ }
}
ret = 0;
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -488,6 +488,8 @@ struct arch_vcpu
/* This variable determines whether nonlazy extended state has been used,
* and thus should be saved/restored. */
bool_t nonlazy_xstate_used;
+
+ uint8_t nr_vmce_banks;
struct paging_vcpu paging;
--- a/xen/include/asm-x86/mce.h
+++ b/xen/include/asm-x86/mce.h
@@ -28,6 +28,7 @@ struct domain_mca_msrs
/* Guest vMCE MSRs virtualization */
extern int vmce_init_msr(struct domain *d);
extern void vmce_destroy_msr(struct domain *d);
+extern void vmce_init_vcpu(struct vcpu *);
extern int vmce_wrmsr(uint32_t msr, uint64_t val);
extern int vmce_rdmsr(uint32_t msr, uint64_t *val);
--- a/xen/include/public/arch-x86/hvm/save.h
+++ b/xen/include/public/arch-x86/hvm/save.h
@@ -585,9 +585,15 @@ struct hvm_viridian_vcpu_context {
DECLARE_HVM_SAVE_TYPE(VIRIDIAN_VCPU, 17, struct hvm_viridian_vcpu_context);
+struct hvm_vmce_vcpu {
+ uint8_t nr_banks;
+};
+
+DECLARE_HVM_SAVE_TYPE(VMCE_VCPU, 18, struct hvm_vmce_vcpu);
+
/*
* Largest type-code in use
*/
-#define HVM_SAVE_CODE_MAX 17
+#define HVM_SAVE_CODE_MAX 18
#endif /* __XEN_PUBLIC_HVM_SAVE_X86_H__ */
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -559,7 +559,7 @@ struct xen_domctl_ext_vcpucontext {
uint32_t vcpu;
/*
* SET: Size of struct (IN)
- * GET: Size of struct (OUT)
+ * GET: Size of struct (OUT, up to 128 bytes)
*/
uint32_t size;
#if defined(__i386__) || defined(__x86_64__)
@@ -571,6 +571,10 @@ struct xen_domctl_ext_vcpucontext {
uint16_t sysenter_callback_cs;
uint8_t syscall32_disables_events;
uint8_t sysenter_disables_events;
+ uint8_t nr_mce_banks;
+ /* This array can be split and used for future extension. */
+ /* It is there just to grow the structure beyond 4.1's size. */
+ uint8_t mbz[9];
#endif
};
typedef struct xen_domctl_ext_vcpucontext xen_domctl_ext_vcpucontext_t;
Attachment:
x86-vmce-sr.patch _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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