[xen staging] x86/svm: Add infrastructure for Bus Lock Threshold

[patchbot@xxxxxxx]

commit 06d2514278ac725f840482e7b42c9e529c99cd10
Author:     Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>
AuthorDate: Wed Jan 21 15:28:53 2026 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Jan 22 13:05:39 2026 +0000

    x86/svm: Add infrastructure for Bus Lock Threshold
    
    Add missing scaffolding to enable BusLock Threshold. That is:
    
      * Add General Intercepts 3
      * Add missing VMEXIT
      * Adjust NPF perf counter base to immediately after the buslock counter
    
    Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>
    Reviewed-by: Teddy Astie <teddy.astie@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/svm/vmcb.c           |  1 +
 xen/arch/x86/hvm/svm/vmcb.h           | 15 +++++++++++++--
 xen/arch/x86/include/asm/hvm/svm.h    |  2 ++
 xen/arch/x86/include/asm/perfc_defn.h |  2 +-
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/vmcb.c b/xen/arch/x86/hvm/svm/vmcb.c
index 72173c8fdd..8734fd2bca 100644
--- a/xen/arch/x86/hvm/svm/vmcb.c
+++ b/xen/arch/x86/hvm/svm/vmcb.c
@@ -435,6 +435,7 @@ static void __init __maybe_unused build_assertions(void)
     BUILD_BUG_ON(offsetof(typeof(vmcb), _pause_filter_thresh) != 0x03c);
     BUILD_BUG_ON(offsetof(typeof(vmcb), _vintr)               != 0x060);
     BUILD_BUG_ON(offsetof(typeof(vmcb), event_inj)            != 0x0a8);
+    BUILD_BUG_ON(offsetof(typeof(vmcb), bus_lock_count)       != 0x120);
 
     /* State Save area */
     BUILD_BUG_ON(offsetof(typeof(vmcb), es)                   != 0x400);
diff --git a/xen/arch/x86/hvm/svm/vmcb.h b/xen/arch/x86/hvm/svm/vmcb.h
index c64386e7ef..69f6047394 100644
--- a/xen/arch/x86/hvm/svm/vmcb.h
+++ b/xen/arch/x86/hvm/svm/vmcb.h
@@ -63,6 +63,11 @@ enum GenericIntercept2bits
     GENERAL2_INTERCEPT_RDPRU   = 1 << 14,
 };
 
+enum GenericIntercept3bits
+{
+    GENERAL3_INTERCEPT_BUS_LOCK = 1 << 5,
+};
+
 enum CRInterceptBits
 {
     CR_INTERCEPT_CR0_READ   = 1 << 0,
@@ -283,6 +288,7 @@ enum VMEXIT_EXITCODE
     VMEXIT_MWAIT_CONDITIONAL= 140, /* 0x8c */
     VMEXIT_XSETBV           = 141, /* 0x8d */
     VMEXIT_RDPRU            = 142, /* 0x8e */
+    VMEXIT_BUS_LOCK         = 165, /* 0xa5 */
     /* Remember to also update VMEXIT_NPF_PERFC! */
     VMEXIT_NPF              = 1024, /* 0x400, nested paging fault */
     /* Remember to also update SVM_PERF_EXIT_REASON_SIZE! */
@@ -400,7 +406,8 @@ struct vmcb_struct {
     u32 _exception_intercepts;  /* offset 0x08 - cleanbit 0 */
     u32 _general1_intercepts;   /* offset 0x0C - cleanbit 0 */
     u32 _general2_intercepts;   /* offset 0x10 - cleanbit 0 */
-    u32 res01[10];
+    u32 _general3_intercepts;   /* offset 0x14 - cleanbit 0 */
+    u32 res01[9];
     u16 _pause_filter_thresh;   /* offset 0x3C - cleanbit 0 */
     u16 _pause_filter_count;    /* offset 0x3E - cleanbit 0 */
     u64 _iopm_base_pa;          /* offset 0x40 - cleanbit 1 */
@@ -484,7 +491,10 @@ struct vmcb_struct {
     u64 nextrip;                /* offset 0xC8 */
     u8  guest_ins_len;          /* offset 0xD0 */
     u8  guest_ins[15];          /* offset 0xD1 */
-    u64 res10a[100];            /* offset 0xE0 pad to save area */
+    u64 res10a[8];              /* offset 0xE0 */
+    u16 bus_lock_count;         /* offset 0x120 */
+    u16 res10b[3];              /* offset 0x122 */
+    u64 res10c[91];             /* offset 0x128 pad to save area */
 
     /* State Save area */
     union {
@@ -579,6 +589,7 @@ VMCB_ACCESSORS(dr_intercepts, intercepts)
 VMCB_ACCESSORS(exception_intercepts, intercepts)
 VMCB_ACCESSORS(general1_intercepts, intercepts)
 VMCB_ACCESSORS(general2_intercepts, intercepts)
+VMCB_ACCESSORS(general3_intercepts, intercepts)
 VMCB_ACCESSORS(pause_filter_count, intercepts)
 VMCB_ACCESSORS(pause_filter_thresh, intercepts)
 VMCB_ACCESSORS(tsc_offset, intercepts)
diff --git a/xen/arch/x86/include/asm/hvm/svm.h 
b/xen/arch/x86/include/asm/hvm/svm.h
index a6d7e4aed3..15f0268be7 100644
--- a/xen/arch/x86/include/asm/hvm/svm.h
+++ b/xen/arch/x86/include/asm/hvm/svm.h
@@ -37,6 +37,7 @@ extern u32 svm_feature_flags;
 #define SVM_FEATURE_VGIF          16 /* Virtual GIF */
 #define SVM_FEATURE_SSS           19 /* NPT Supervisor Shadow Stacks */
 #define SVM_FEATURE_SPEC_CTRL     20 /* MSR_SPEC_CTRL virtualisation */
+#define SVM_FEATURE_BUS_LOCK      29 /* Bus Lock Threshold */
 
 static inline bool cpu_has_svm_feature(unsigned int feat)
 {
@@ -56,6 +57,7 @@ static inline bool cpu_has_svm_feature(unsigned int feat)
 #define cpu_has_svm_vloadsave cpu_has_svm_feature(SVM_FEATURE_VLOADSAVE)
 #define cpu_has_svm_sss       cpu_has_svm_feature(SVM_FEATURE_SSS)
 #define cpu_has_svm_spec_ctrl cpu_has_svm_feature(SVM_FEATURE_SPEC_CTRL)
+#define cpu_has_svm_bus_lock  cpu_has_svm_feature(SVM_FEATURE_BUS_LOCK)
 
 #define MSR_INTERCEPT_NONE    0
 #define MSR_INTERCEPT_READ    1
diff --git a/xen/arch/x86/include/asm/perfc_defn.h 
b/xen/arch/x86/include/asm/perfc_defn.h
index d6127cb91e..ac7439b992 100644
--- a/xen/arch/x86/include/asm/perfc_defn.h
+++ b/xen/arch/x86/include/asm/perfc_defn.h
@@ -7,7 +7,7 @@ PERFCOUNTER_ARRAY(exceptions,           "exceptions", 32)
 #ifdef CONFIG_HVM
 
 #define VMX_PERF_EXIT_REASON_SIZE 76
-#define VMEXIT_NPF_PERFC 143
+#define VMEXIT_NPF_PERFC 166
 #define SVM_PERF_EXIT_REASON_SIZE (VMEXIT_NPF_PERFC + 1)
 PERFCOUNTER_ARRAY(vmexits,              "vmexits",
                   MAX(VMX_PERF_EXIT_REASON_SIZE, SVM_PERF_EXIT_REASON_SIZE))
--
generated by git-patchbot for /home/xen/git/xen.git#staging