[xen master] xen/arm: Do not route NS phys timer IRQ to Xen

[patchbot@xxxxxxx]

commit 8d30b9e32c462fdfab4207bfcd31ed63749c4f28
Author:     Michal Orzel <michal.orzel@xxxxxxx>
AuthorDate: Fri Oct 28 14:49:37 2022 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Fri Dec 9 18:27:09 2022 +0000

    xen/arm: Do not route NS phys timer IRQ to Xen
    
    At the moment, we route NS phys timer IRQ to Xen even though it does not
    make use of this timer. Xen uses hypervisor timer for itself and the
    physical timer is fully emulated, hence there is nothing that can trigger
    such IRQ. This means that requesting/releasing IRQ ends up as a deadcode
    as it has no impact on the functional behavior, whereas the code within
    a handler ends up being unreachable. This is a left over from the early
    days when the CNTHP IRQ was buggy on the HW model used for testing and we
    had to use the CNTP instead.
    
    Remove the calls to {request/release}_irq for this timer as well as the
    code within the handler. Since timer_interrupt handler is now only used
    by the CNTHP, refactor it as follows:
     - rename it to htimer_interrupt to reflect its purpose,
     - remove the IRQ affiliation test,
     - invert the condition to avoid indented code and use unlikely,
     - improve readability by adding new lines \btw code and comments.
    
    Keep the calls to zero the CNTP_CTL_EL0 register for sanity and also
    remove the corresponding perf counter definition.
    
    Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
    Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 xen/arch/arm/include/asm/perfc_defn.h |  1 -
 xen/arch/arm/time.c                   | 34 +++++++++++-----------------------
 2 files changed, 11 insertions(+), 24 deletions(-)

diff --git a/xen/arch/arm/include/asm/perfc_defn.h 
b/xen/arch/arm/include/asm/perfc_defn.h
index 31f071222b..3ab0391175 100644
--- a/xen/arch/arm/include/asm/perfc_defn.h
+++ b/xen/arch/arm/include/asm/perfc_defn.h
@@ -70,7 +70,6 @@ PERFCOUNTER(spis,                 "#SPIs")
 PERFCOUNTER(guest_irqs,           "#GUEST-IRQS")
 
 PERFCOUNTER(hyp_timer_irqs,   "Hypervisor timer interrupts")
-PERFCOUNTER(phys_timer_irqs,  "Physical timer interrupts")
 PERFCOUNTER(virt_timer_irqs,  "Virtual timer interrupts")
 PERFCOUNTER(maintenance_irqs, "Maintenance interrupts")
 
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index dec53b5f7d..0054cf2b7b 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -220,27 +220,18 @@ int reprogram_timer(s_time_t timeout)
 }
 
 /* Handle the firing timer */
-static void timer_interrupt(int irq, void *dev_id, struct cpu_user_regs *regs)
+static void htimer_interrupt(int irq, void *dev_id, struct cpu_user_regs *regs)
 {
-    if ( irq == (timer_irq[TIMER_HYP_PPI]) &&
-         READ_SYSREG(CNTHP_CTL_EL2) & CNTx_CTL_PENDING )
-    {
-        perfc_incr(hyp_timer_irqs);
-        /* Signal the generic timer code to do its work */
-        raise_softirq(TIMER_SOFTIRQ);
-        /* Disable the timer to avoid more interrupts */
-        WRITE_SYSREG(0, CNTHP_CTL_EL2);
-    }
+    if ( unlikely(!(READ_SYSREG(CNTHP_CTL_EL2) & CNTx_CTL_PENDING)) )
+        return;
 
-    if ( irq == (timer_irq[TIMER_PHYS_NONSECURE_PPI]) &&
-         READ_SYSREG(CNTP_CTL_EL0) & CNTx_CTL_PENDING )
-    {
-        perfc_incr(phys_timer_irqs);
-        /* Signal the generic timer code to do its work */
-        raise_softirq(TIMER_SOFTIRQ);
-        /* Disable the timer to avoid more interrupts */
-        WRITE_SYSREG(0, CNTP_CTL_EL0);
-    }
+    perfc_incr(hyp_timer_irqs);
+
+    /* Signal the generic timer code to do its work */
+    raise_softirq(TIMER_SOFTIRQ);
+
+    /* Disable the timer to avoid more interrupts */
+    WRITE_SYSREG(0, CNTHP_CTL_EL2);
 }
 
 static void vtimer_interrupt(int irq, void *dev_id, struct cpu_user_regs *regs)
@@ -302,12 +293,10 @@ void init_timer_interrupt(void)
     WRITE_SYSREG(0, CNTHP_CTL_EL2);   /* Hypervisor's timer disabled */
     isb();
 
-    request_irq(timer_irq[TIMER_HYP_PPI], 0, timer_interrupt,
+    request_irq(timer_irq[TIMER_HYP_PPI], 0, htimer_interrupt,
                 "hyptimer", NULL);
     request_irq(timer_irq[TIMER_VIRT_PPI], 0, vtimer_interrupt,
                    "virtimer", NULL);
-    request_irq(timer_irq[TIMER_PHYS_NONSECURE_PPI], 0, timer_interrupt,
-                "phytimer", NULL);
 
     check_timer_irq_cfg(timer_irq[TIMER_HYP_PPI], "hypervisor");
     check_timer_irq_cfg(timer_irq[TIMER_VIRT_PPI], "virtual");
@@ -326,7 +315,6 @@ static void deinit_timer_interrupt(void)
 
     release_irq(timer_irq[TIMER_HYP_PPI], NULL);
     release_irq(timer_irq[TIMER_VIRT_PPI], NULL);
-    release_irq(timer_irq[TIMER_PHYS_NONSECURE_PPI], NULL);
 }
 
 /* Wait a set number of microseconds */
--
generated by git-patchbot for /home/xen/git/xen.git#master