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[Xen-devel] [PATCH v6 2/6] x86/paging: add TLB flush hooks



Add shadow and hap implementation specific helpers to perform guest
TLB flushes. Note that the code for both is exactly the same at the
moment, and is copied from hvm_flush_vcpu_tlb. This will be changed by
further patches that will add implementation specific optimizations to
them.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Wei Liu <wl@xxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
---
Changes since v5:
 - Make the flush tlb operation a paging_mode hook.

Changes since v3:
 - Fix stray newline removal.
 - Fix return of shadow_flush_tlb dummy function.
---
 xen/arch/x86/hvm/hvm.c               | 56 +--------------------------
 xen/arch/x86/hvm/viridian/viridian.c |  2 +-
 xen/arch/x86/mm/hap/hap.c            | 58 ++++++++++++++++++++++++++++
 xen/arch/x86/mm/shadow/common.c      | 55 ++++++++++++++++++++++++++
 xen/arch/x86/mm/shadow/multi.c       |  1 +
 xen/arch/x86/mm/shadow/private.h     |  4 ++
 xen/include/asm-x86/hvm/hvm.h        |  3 --
 xen/include/asm-x86/paging.h         | 10 +++++
 8 files changed, 130 insertions(+), 59 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index db5d7b4d30..a2abad9f76 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3988,60 +3988,6 @@ static void hvm_s3_resume(struct domain *d)
     }
 }
 
-bool hvm_flush_vcpu_tlb(bool (*flush_vcpu)(void *ctxt, struct vcpu *v),
-                        void *ctxt)
-{
-    static DEFINE_PER_CPU(cpumask_t, flush_cpumask);
-    cpumask_t *mask = &this_cpu(flush_cpumask);
-    struct domain *d = current->domain;
-    struct vcpu *v;
-
-    /* Avoid deadlock if more than one vcpu tries this at the same time. */
-    if ( !spin_trylock(&d->hypercall_deadlock_mutex) )
-        return false;
-
-    /* Pause all other vcpus. */
-    for_each_vcpu ( d, v )
-        if ( v != current && flush_vcpu(ctxt, v) )
-            vcpu_pause_nosync(v);
-
-    /* Now that all VCPUs are signalled to deschedule, we wait... */
-    for_each_vcpu ( d, v )
-        if ( v != current && flush_vcpu(ctxt, v) )
-            while ( !vcpu_runnable(v) && v->is_running )
-                cpu_relax();
-
-    /* All other vcpus are paused, safe to unlock now. */
-    spin_unlock(&d->hypercall_deadlock_mutex);
-
-    cpumask_clear(mask);
-
-    /* Flush paging-mode soft state (e.g., va->gfn cache; PAE PDPE cache). */
-    for_each_vcpu ( d, v )
-    {
-        unsigned int cpu;
-
-        if ( !flush_vcpu(ctxt, v) )
-            continue;
-
-        paging_update_cr3(v, false);
-
-        cpu = read_atomic(&v->dirty_cpu);
-        if ( is_vcpu_dirty_cpu(cpu) )
-            __cpumask_set_cpu(cpu, mask);
-    }
-
-    /* Flush TLBs on all CPUs with dirty vcpu state. */
-    flush_tlb_mask(mask);
-
-    /* Done. */
-    for_each_vcpu ( d, v )
-        if ( v != current && flush_vcpu(ctxt, v) )
-            vcpu_unpause(v);
-
-    return true;
-}
-
 static bool always_flush(void *ctxt, struct vcpu *v)
 {
     return true;
@@ -4052,7 +3998,7 @@ static int hvmop_flush_tlb_all(void)
     if ( !is_hvm_domain(current->domain) )
         return -EINVAL;
 
-    return hvm_flush_vcpu_tlb(always_flush, NULL) ? 0 : -ERESTART;
+    return paging_flush_tlb(always_flush, NULL) ? 0 : -ERESTART;
 }
 
 static int hvmop_set_evtchn_upcall_vector(
diff --git a/xen/arch/x86/hvm/viridian/viridian.c 
b/xen/arch/x86/hvm/viridian/viridian.c
index cd8f210198..977c1bc54f 100644
--- a/xen/arch/x86/hvm/viridian/viridian.c
+++ b/xen/arch/x86/hvm/viridian/viridian.c
@@ -609,7 +609,7 @@ int viridian_hypercall(struct cpu_user_regs *regs)
          * A false return means that another vcpu is currently trying
          * a similar operation, so back off.
          */
-        if ( !hvm_flush_vcpu_tlb(need_flush, &input_params.vcpu_mask) )
+        if ( !paging_flush_tlb(need_flush, &input_params.vcpu_mask) )
             return HVM_HCALL_preempted;
 
         output.rep_complete = input.rep_count;
diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index 3d93f3451c..5616235bd8 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -669,6 +669,60 @@ static void hap_update_cr3(struct vcpu *v, int do_locking, 
bool noflush)
     hvm_update_guest_cr3(v, noflush);
 }
 
+static bool flush_tlb(bool (*flush_vcpu)(void *ctxt, struct vcpu *v),
+                      void *ctxt)
+{
+    static DEFINE_PER_CPU(cpumask_t, flush_cpumask);
+    cpumask_t *mask = &this_cpu(flush_cpumask);
+    struct domain *d = current->domain;
+    struct vcpu *v;
+
+    /* Avoid deadlock if more than one vcpu tries this at the same time. */
+    if ( !spin_trylock(&d->hypercall_deadlock_mutex) )
+        return false;
+
+    /* Pause all other vcpus. */
+    for_each_vcpu ( d, v )
+        if ( v != current && flush_vcpu(ctxt, v) )
+            vcpu_pause_nosync(v);
+
+    /* Now that all VCPUs are signalled to deschedule, we wait... */
+    for_each_vcpu ( d, v )
+        if ( v != current && flush_vcpu(ctxt, v) )
+            while ( !vcpu_runnable(v) && v->is_running )
+                cpu_relax();
+
+    /* All other vcpus are paused, safe to unlock now. */
+    spin_unlock(&d->hypercall_deadlock_mutex);
+
+    cpumask_clear(mask);
+
+    /* Flush paging-mode soft state (e.g., va->gfn cache; PAE PDPE cache). */
+    for_each_vcpu ( d, v )
+    {
+        unsigned int cpu;
+
+        if ( !flush_vcpu(ctxt, v) )
+            continue;
+
+        paging_update_cr3(v, false);
+
+        cpu = read_atomic(&v->dirty_cpu);
+        if ( is_vcpu_dirty_cpu(cpu) )
+            __cpumask_set_cpu(cpu, mask);
+    }
+
+    /* Flush TLBs on all CPUs with dirty vcpu state. */
+    flush_tlb_mask(mask);
+
+    /* Done. */
+    for_each_vcpu ( d, v )
+        if ( v != current && flush_vcpu(ctxt, v) )
+            vcpu_unpause(v);
+
+    return true;
+}
+
 const struct paging_mode *
 hap_paging_get_mode(struct vcpu *v)
 {
@@ -781,6 +835,7 @@ static const struct paging_mode hap_paging_real_mode = {
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
     .write_p2m_entry        = hap_write_p2m_entry,
+    .flush_tlb              = flush_tlb,
     .guest_levels           = 1
 };
 
@@ -792,6 +847,7 @@ static const struct paging_mode hap_paging_protected_mode = 
{
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
     .write_p2m_entry        = hap_write_p2m_entry,
+    .flush_tlb              = flush_tlb,
     .guest_levels           = 2
 };
 
@@ -803,6 +859,7 @@ static const struct paging_mode hap_paging_pae_mode = {
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
     .write_p2m_entry        = hap_write_p2m_entry,
+    .flush_tlb              = flush_tlb,
     .guest_levels           = 3
 };
 
@@ -814,6 +871,7 @@ static const struct paging_mode hap_paging_long_mode = {
     .update_cr3             = hap_update_cr3,
     .update_paging_modes    = hap_update_paging_modes,
     .write_p2m_entry        = hap_write_p2m_entry,
+    .flush_tlb              = flush_tlb,
     .guest_levels           = 4
 };
 
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index cba3ab1eba..121ddf1255 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -3357,6 +3357,61 @@ out:
     return rc;
 }
 
+/* Fluhs TLB of selected vCPUs. */
+bool shadow_flush_tlb(bool (*flush_vcpu)(void *ctxt, struct vcpu *v),
+                      void *ctxt)
+{
+    static DEFINE_PER_CPU(cpumask_t, flush_cpumask);
+    cpumask_t *mask = &this_cpu(flush_cpumask);
+    struct domain *d = current->domain;
+    struct vcpu *v;
+
+    /* Avoid deadlock if more than one vcpu tries this at the same time. */
+    if ( !spin_trylock(&d->hypercall_deadlock_mutex) )
+        return false;
+
+    /* Pause all other vcpus. */
+    for_each_vcpu ( d, v )
+        if ( v != current && flush_vcpu(ctxt, v) )
+            vcpu_pause_nosync(v);
+
+    /* Now that all VCPUs are signalled to deschedule, we wait... */
+    for_each_vcpu ( d, v )
+        if ( v != current && flush_vcpu(ctxt, v) )
+            while ( !vcpu_runnable(v) && v->is_running )
+                cpu_relax();
+
+    /* All other vcpus are paused, safe to unlock now. */
+    spin_unlock(&d->hypercall_deadlock_mutex);
+
+    cpumask_clear(mask);
+
+    /* Flush paging-mode soft state (e.g., va->gfn cache; PAE PDPE cache). */
+    for_each_vcpu ( d, v )
+    {
+        unsigned int cpu;
+
+        if ( !flush_vcpu(ctxt, v) )
+            continue;
+
+        paging_update_cr3(v, false);
+
+        cpu = read_atomic(&v->dirty_cpu);
+        if ( is_vcpu_dirty_cpu(cpu) )
+            __cpumask_set_cpu(cpu, mask);
+    }
+
+    /* Flush TLBs on all CPUs with dirty vcpu state. */
+    flush_tlb_mask(mask);
+
+    /* Done. */
+    for_each_vcpu ( d, v )
+        if ( v != current && flush_vcpu(ctxt, v) )
+            vcpu_unpause(v);
+
+    return true;
+}
+
 /**************************************************************************/
 /* Shadow-control XEN_DOMCTL dispatcher */
 
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 26798b317c..b6afc0fba4 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -4873,6 +4873,7 @@ const struct paging_mode sh_paging_mode = {
     .update_cr3                    = sh_update_cr3,
     .update_paging_modes           = shadow_update_paging_modes,
     .write_p2m_entry               = shadow_write_p2m_entry,
+    .flush_tlb                     = shadow_flush_tlb,
     .guest_levels                  = GUEST_PAGING_LEVELS,
     .shadow.detach_old_tables      = sh_detach_old_tables,
 #ifdef CONFIG_PV
diff --git a/xen/arch/x86/mm/shadow/private.h b/xen/arch/x86/mm/shadow/private.h
index 3217777921..e8b028a365 100644
--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -814,6 +814,10 @@ static inline int sh_check_page_has_no_refs(struct 
page_info *page)
              ((count & PGC_allocated) ? 1 : 0) );
 }
 
+/* Flush the TLB of the selected vCPUs. */
+bool shadow_flush_tlb(bool (*flush_vcpu)(void *ctxt, struct vcpu *v),
+                      void *ctxt);
+
 #endif /* _XEN_SHADOW_PRIVATE_H */
 
 /*
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 24da824cbf..aae00a7860 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -334,9 +334,6 @@ const char *hvm_efer_valid(const struct vcpu *v, uint64_t 
value,
                            signed int cr0_pg);
 unsigned long hvm_cr4_guest_valid_bits(const struct domain *d, bool restore);
 
-bool hvm_flush_vcpu_tlb(bool (*flush_vcpu)(void *ctxt, struct vcpu *v),
-                        void *ctxt);
-
 int hvm_copy_context_and_params(struct domain *src, struct domain *dst);
 
 #ifdef CONFIG_HVM
diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
index 7544f73121..051161481c 100644
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -140,6 +140,9 @@ struct paging_mode {
                                             unsigned long gfn,
                                             l1_pgentry_t *p, l1_pgentry_t new,
                                             unsigned int level);
+    bool          (*flush_tlb             )(bool (*flush_vcpu)(void *ctxt,
+                                                               struct vcpu *v),
+                                            void *ctxt);
 
     unsigned int guest_levels;
 
@@ -397,6 +400,13 @@ static always_inline unsigned int 
paging_max_paddr_bits(const struct domain *d)
     return bits;
 }
 
+static inline bool paging_flush_tlb(bool (*flush_vcpu)(void *ctxt,
+                                                       struct vcpu *v),
+                                    void *ctxt)
+{
+    return paging_get_hostmode(current)->flush_tlb(flush_vcpu, ctxt);
+}
+
 #endif /* XEN_PAGING_H */
 
 /*
-- 
2.25.0


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