[xen staging] x86/svm: Use flush-by-asid when available

[patchbot@xxxxxxx]

commit 64b1da5a2fcf37e3542c277fde194ff3e8bba2d2
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Feb 12 18:37:04 2019 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu May 7 13:50:38 2020 +0100

    x86/svm: Use flush-by-asid when available
    
    AMD Fam15h processors introduced the flush-by-asid feature, for more fine
    grain flushing purposes.
    
    Flushing everything including ASID 0 (i.e. Xen context) is an an 
unnecesserily
    large hammer, and never necessary in the context of guest TLBs needing
    invalidating.
    
    When available, use TLB_CTRL_FLUSH_ASID in preference to TLB_CTRL_FLUSH_ALL.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/svm/asid.c       | 9 ++++++---
 xen/include/asm-x86/hvm/svm/svm.h | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/asid.c b/xen/arch/x86/hvm/svm/asid.c
index 9be90058c7..ab06dd3f3a 100644
--- a/xen/arch/x86/hvm/svm/asid.c
+++ b/xen/arch/x86/hvm/svm/asid.c
@@ -18,6 +18,7 @@
 #include <asm/amd.h>
 #include <asm/hvm/nestedhvm.h>
 #include <asm/hvm/svm/asid.h>
+#include <asm/hvm/svm/svm.h>
 
 void svm_asid_init(const struct cpuinfo_x86 *c)
 {
@@ -47,15 +48,17 @@ void svm_asid_handle_vmrun(void)
     if ( p_asid->asid == 0 )
     {
         vmcb_set_guest_asid(vmcb, 1);
-        /* TODO: investigate using TLB_CTRL_FLUSH_ASID here instead. */
-        vmcb->tlb_control = TLB_CTRL_FLUSH_ALL;
+        vmcb->tlb_control =
+            cpu_has_svm_flushbyasid ? TLB_CTRL_FLUSH_ASID : TLB_CTRL_FLUSH_ALL;
         return;
     }
 
     if ( vmcb_get_guest_asid(vmcb) != p_asid->asid )
         vmcb_set_guest_asid(vmcb, p_asid->asid);
 
-    vmcb->tlb_control = need_flush ? TLB_CTRL_FLUSH_ALL : TLB_CTRL_NO_FLUSH;
+    vmcb->tlb_control =
+        !need_flush ? TLB_CTRL_NO_FLUSH :
+        cpu_has_svm_flushbyasid ? TLB_CTRL_FLUSH_ASID : TLB_CTRL_FLUSH_ALL;
 }
 
 /*
diff --git a/xen/include/asm-x86/hvm/svm/svm.h 
b/xen/include/asm-x86/hvm/svm/svm.h
index 16a994ec74..cd71402cbb 100644
--- a/xen/include/asm-x86/hvm/svm/svm.h
+++ b/xen/include/asm-x86/hvm/svm/svm.h
@@ -79,6 +79,7 @@ extern u32 svm_feature_flags;
 #define cpu_has_svm_svml      cpu_has_svm_feature(SVM_FEATURE_SVML)
 #define cpu_has_svm_nrips     cpu_has_svm_feature(SVM_FEATURE_NRIPS)
 #define cpu_has_svm_cleanbits cpu_has_svm_feature(SVM_FEATURE_VMCBCLEAN)
+#define cpu_has_svm_flushbyasid cpu_has_svm_feature(SVM_FEATURE_FLUSHBYASID)
 #define cpu_has_svm_decode    cpu_has_svm_feature(SVM_FEATURE_DECODEASSISTS)
 #define cpu_has_svm_vgif      cpu_has_svm_feature(SVM_FEATURE_VGIF)
 #define cpu_has_pause_filter  cpu_has_svm_feature(SVM_FEATURE_PAUSEFILTER)
--
generated by git-patchbot for /home/xen/git/xen.git#staging