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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v5 4/7] X86: generic MSRs save/restore
x86: generic MSRs save/restore
This patch introduces a generic MSRs save/restore mechanism, so that
in the future new MSRs save/restore could be added w/ smaller change
than the full blown addition of a new save/restore type.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1127,10 +1127,110 @@ static int hvm_load_cpu_xsave_states(str
return 0;
}
-/* We need variable length data chunk for xsave area, hence customized
- * declaration other than HVM_REGISTER_SAVE_RESTORE.
+#define HVM_CPU_MSR_SIZE(cnt) offsetof(struct hvm_msr, msr[cnt])
+static unsigned int __read_mostly msr_count_max;
+
+static int hvm_save_cpu_msrs(struct domain *d, hvm_domain_context_t *h)
+{
+ struct vcpu *v;
+
+ if ( !msr_count_max )
+ return 0;
ASSERT( msr_count_mas ); ?
+
+ for_each_vcpu ( d, v )
+ {
+ struct hvm_msr *ctxt;
+ unsigned int i;
+
+ if ( _hvm_init_entry(h, CPU_MSR_CODE, v->vcpu_id,
+ HVM_CPU_MSR_SIZE(msr_count_max)) )
+ return 1;
+ ctxt = (struct hvm_msr *)&h->data[h->cur];
+ ctxt->count = 0;
+
+ if ( hvm_funcs.save_msr )
+ hvm_funcs.save_msr(v, ctxt);
+
+ for ( i = 0; i < ctxt->count; ++i )
+ ctxt->msr[i]._rsvd = 0;
What _rsvd for? seems not used at the patches.
+
+ if ( ctxt->count )
+ h->cur += HVM_CPU_MSR_SIZE(ctxt->count);
+ else
+ h->cur -= sizeof(struct hvm_save_descriptor);
+ }
+
+ return 0;
+}
+
+static int hvm_load_cpu_msrs(struct domain *d, hvm_domain_context_t *h)
+{
+ unsigned int i, vcpuid = hvm_load_instance(h);
+ struct vcpu *v;
+ const struct hvm_save_descriptor *desc;
+ const struct hvm_msr *ctxt;
+ int err = 0;
+
+ if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) == NULL )
+ {
+ dprintk(XENLOG_G_ERR, "HVM restore: dom%d has no vcpu%u\n",
+ d->domain_id, vcpuid);
+ return -EINVAL;
+ }
+
+ /* Customized checking for entry since our entry is of variable length */
+ desc = (struct hvm_save_descriptor *)&h->data[h->cur];
+ if ( sizeof (*desc) > h->size - h->cur)
+ {
+ printk(XENLOG_G_WARNING
+ "HVM%d.%d restore: not enough data left to read MSR
descriptor\n",
+ d->domain_id, vcpuid);
+ return -ENODATA;
+ }
+ if ( desc->length + sizeof (*desc) > h->size - h->cur)
+ {
+ printk(XENLOG_G_WARNING
+ "HVM%d.%d restore: not enough data left to read %u MSR bytes\n",
+ d->domain_id, vcpuid, desc->length);
+ return -ENODATA;
+ }
+ if ( desc->length < HVM_CPU_MSR_SIZE(1) )
+ {
+ printk(XENLOG_G_WARNING
+ "HVM%d.%d restore mismatch: MSR length %u < %zu\n",
+ d->domain_id, vcpuid, desc->length, HVM_CPU_MSR_SIZE(1));
+ return -EINVAL;
+ }
+
+ h->cur += sizeof(*desc);
+ ctxt = (struct hvm_msr *)&h->data[h->cur];
+ h->cur += desc->length;
+
+ if ( desc->length != HVM_CPU_MSR_SIZE(ctxt->count) )
+ {
+ printk(XENLOG_G_WARNING
+ "HVM%d.%d restore mismatch: MSR length %u != %zu\n",
+ d->domain_id, vcpuid, desc->length,
+ HVM_CPU_MSR_SIZE(ctxt->count));
+ return -EOPNOTSUPP;
+ }
+ /* Checking finished */
+
+ for ( i = 0; i < ctxt->count; ++i )
+ {
+ if ( hvm_funcs.load_msr )
+ err = hvm_funcs.load_msr(v, &ctxt->msr[i]);
+ if ( err )
+ break;
+ }
Is it for vmx/svm specific msrs, or, will extend to generic msrs?
If these patches are generic save/load mechanism supporting generic msrs and
vmx/sve specific msrs, it need update here.
+
+ return err;
+}
+
+/* We need variable length data chunks for XSAVE area and MSRs, hence
+ * a custom declaration rather than HVM_REGISTER_SAVE_RESTORE.
*/
-static int __init __hvm_register_CPU_XSAVE_save_and_restore(void)
+static int __init hvm_register_CPU_save_and_restore(void)
{
hvm_register_savevm(CPU_XSAVE_CODE,
"CPU_XSAVE",
@@ -1139,9 +1239,22 @@ static int __init __hvm_register_CPU_XSA
HVM_CPU_XSAVE_SIZE(xfeature_mask) +
sizeof(struct hvm_save_descriptor),
HVMSR_PER_VCPU);
+
+ if ( hvm_funcs.init_msr )
+ msr_count_max += hvm_funcs.init_msr();
+
+ if ( msr_count_max )
+ hvm_register_savevm(CPU_MSR_CODE,
+ "CPU_MSR",
+ hvm_save_cpu_msrs,
+ hvm_load_cpu_msrs,
+ HVM_CPU_MSR_SIZE(msr_count_max) +
+ sizeof(struct hvm_save_descriptor),
+ HVMSR_PER_VCPU);
+
return 0;
}
-__initcall(__hvm_register_CPU_XSAVE_save_and_restore);
+__initcall(hvm_register_CPU_save_and_restore);
int hvm_vcpu_initialise(struct vcpu *v)
{
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -109,6 +109,10 @@ struct hvm_function_table {
void (*save_cpu_ctxt)(struct vcpu *v, struct hvm_hw_cpu *ctxt);
int (*load_cpu_ctxt)(struct vcpu *v, struct hvm_hw_cpu *ctxt);
+ unsigned int (*init_msr)(void);
+ void (*save_msr)(struct vcpu *, struct hvm_msr *);
+ int (*load_msr)(struct vcpu *, const struct hvm_one_msr *);
+
/* Examine specifics of the guest state. */
unsigned int (*get_interrupt_shadow)(struct vcpu *v);
void (*set_interrupt_shadow)(struct vcpu *v, unsigned int intr_shadow);
--- a/xen/include/public/arch-x86/hvm/save.h
+++ b/xen/include/public/arch-x86/hvm/save.h
@@ -592,9 +592,21 @@ struct hvm_tsc_adjust {
DECLARE_HVM_SAVE_TYPE(TSC_ADJUST, 19, struct hvm_tsc_adjust);
+
+struct hvm_msr {
+ uint32_t count;
+ struct hvm_one_msr {
+ uint32_t index;
+ uint32_t _rsvd;
+ uint64_t val;
+ } msr[1 /* variable size */];
+};
+
+#define CPU_MSR_CODE 16
+
It's incorrect, conflict with CPU_XSAVE_CODE and panic when
hvm_register_savevm(CPU_MSR_CODE, ...)
Why not 20?
/*
* Largest type-code in use
*/
-#define HVM_SAVE_CODE_MAX 19
+#define HVM_SAVE_CODE_MAX 20
#endif /* __XEN_PUBLIC_HVM_SAVE_X86_H__ */
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