[Xen-devel] [PATCH 05/12] Placeholder for handling Group1 register traps

[mjaggi@xxxxxxxxxxxxxxxxxx]

From: Manish Jaggi <manish.jaggi@xxxxxxxxxx>

Since this is a SoC errata and trapping of certain group1 registers
should not affect the normal flow. A new file vsysreg_errata.c is added.

Function vgic_v3_handle_cpuif_access is called from do_trap_guest_sync
if ARM64_WORKAROUND_CAVIUM_30115 capability is found.

A flag skip_hyp_tail is introduced in struct cpu_info. This flag specifies
that leave_hypervisor_tail not to be called when handling group1 traps
under this errata.

Signed-off-by: Manish Jaggi <manish.jaggi@xxxxxxxxxx>
---
 xen/arch/arm/arm64/Makefile         |  1 +
 xen/arch/arm/arm64/vsysreg_errata.c | 28 ++++++++++++++++++++++++++++
 xen/arch/arm/traps.c                | 20 ++++++++++++++++++++
 xen/include/asm-arm/arm64/traps.h   |  3 ++-
 xen/include/asm-arm/current.h       |  1 +
 5 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile
index 718fe44455..19440c3d8c 100644
--- a/xen/arch/arm/arm64/Makefile
+++ b/xen/arch/arm/arm64/Makefile
@@ -11,3 +11,4 @@ obj-y += smpboot.o
 obj-y += traps.o
 obj-y += vfp.o
 obj-y += vsysreg.o
+obj-$(CONFIG_CAVIUM_ERRATUM_30115) += vsysreg_errata.o
diff --git a/xen/arch/arm/arm64/vsysreg_errata.c 
b/xen/arch/arm/arm64/vsysreg_errata.c
new file mode 100644
index 0000000000..6af162bdf7
--- /dev/null
+++ b/xen/arch/arm/arm64/vsysreg_errata.c
@@ -0,0 +1,28 @@
+#include <asm/current.h>
+#include <asm/regs.h>
+#include <asm/traps.h>
+#include <asm/system.h>
+
+bool vgic_v3_handle_cpuif_access(struct cpu_user_regs *regs, const union hsr 
hsr)
+{
+    bool ret = 0;
+
+    local_irq_disable();
+    if ( hsr.ec != HSR_EC_SYSREG )
+    {
+        ret = 1;
+        goto end;
+    }
+
+    switch ( hsr.bits & HSR_SYSREG_REGS_MASK )
+    {
+    default:
+        ret = 1;
+        break;
+    }
+end:
+    local_irq_enable();
+
+    return ret;
+}
+
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index f6f6de3691..9d08cd6ad3 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -40,6 +40,7 @@
 #include <asm/acpi.h>
 #include <asm/cpuerrata.h>
 #include <asm/cpufeature.h>
+#include <asm/cpuerrata.h>
 #include <asm/debugger.h>
 #include <asm/event.h>
 #include <asm/flushtlb.h>
@@ -2103,6 +2104,21 @@ void do_trap_guest_sync(struct cpu_user_regs *regs)
 {
     const union hsr hsr = { .bits = regs->hsr };
 
+#ifdef CONFIG_CAVIUM_ERRATUM_30115
+    if ( cpus_have_cap(ARM64_WORKAROUND_CAVIUM_30115) )
+    {
+        int ret;
+        get_cpu_info()->skip_hyp_tail = 0;
+        ret  = vgic_v3_handle_cpuif_access(regs, hsr);
+        if ( !ret )
+        {
+            advance_pc(regs, hsr);
+            get_cpu_info()->skip_hyp_tail = 1;
+            return;
+        }
+    }
+#endif
+
     enter_hypervisor_head(regs);
 
     switch (hsr.ec) {
@@ -2295,6 +2311,10 @@ void do_trap_fiq(struct cpu_user_regs *regs)
 
 void leave_hypervisor_tail(void)
 {
+#ifdef CONFIG_CAVIUM_ERRATUM_30115
+    if ( get_cpu_info()->skip_hyp_tail )
+        return;
+#endif
     while (1)
     {
         local_irq_disable();
diff --git a/xen/include/asm-arm/arm64/traps.h 
b/xen/include/asm-arm/arm64/traps.h
index 2379b578cb..a5ae93ec11 100644
--- a/xen/include/asm-arm/arm64/traps.h
+++ b/xen/include/asm-arm/arm64/traps.h
@@ -2,7 +2,8 @@
 #define __ASM_ARM64_TRAPS__
 
 void inject_undef64_exception(struct cpu_user_regs *regs, int instr_len);
-
+bool vgic_v3_handle_cpuif_access(struct cpu_user_regs *regs,
+                                const union hsr hsr);
 void do_sysreg(struct cpu_user_regs *regs,
                const union hsr hsr);
 
diff --git a/xen/include/asm-arm/current.h b/xen/include/asm-arm/current.h
index 7a0971fdea..dacf3adc85 100644
--- a/xen/include/asm-arm/current.h
+++ b/xen/include/asm-arm/current.h
@@ -22,6 +22,7 @@ struct cpu_info {
     struct cpu_user_regs guest_cpu_user_regs;
     unsigned long elr;
     unsigned int pad;
+    bool skip_hyp_tail;
 };
 
 static inline struct cpu_info *get_cpu_info(void)
-- 
2.14.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel