[xen staging] x86/APIC: Switch flat driver to use phys dst for ext ints

[patchbot@xxxxxxx]

commit dcbf8210f3f3a49626341355308010eb92194b85
Author:     Matthew Barnes <matthew.barnes@xxxxxxxxx>
AuthorDate: Wed Oct 9 09:54:48 2024 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Oct 9 09:54:48 2024 +0200

    x86/APIC: Switch flat driver to use phys dst for ext ints
    
    External interrupts via logical delivery mode in xAPIC do not benefit
    from targeting multiple CPUs and instead simply bloat up the vector
    space.
    
    However the xAPIC flat driver currently uses logical delivery for
    external interrupts.
    
    This patch switches the xAPIC flat driver to use physical destination
    mode for external interrupts, instead of logical destination mode.
    
    This patch also applies the following non-functional changes:
    - Remove now unused logical flat functions
    - Expand GENAPIC_FLAT and GENAPIC_PHYS macros, and delete them.
    
    Resolves: https://gitlab.com/xen-project/xen/-/issues/194
    Signed-off-by: Matthew Barnes <matthew.barnes@xxxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/genapic/bigsmp.c      |  8 +++++++-
 xen/arch/x86/genapic/default.c     |  8 +++++++-
 xen/arch/x86/genapic/delivery.c    | 10 ----------
 xen/arch/x86/include/asm/genapic.h | 18 ------------------
 4 files changed, 14 insertions(+), 30 deletions(-)

diff --git a/xen/arch/x86/genapic/bigsmp.c b/xen/arch/x86/genapic/bigsmp.c
index e97e4453a0..b2e7218452 100644
--- a/xen/arch/x86/genapic/bigsmp.c
+++ b/xen/arch/x86/genapic/bigsmp.c
@@ -46,5 +46,11 @@ static int __init cf_check probe_bigsmp(void)
 
 const struct genapic __initconst_cf_clobber apic_bigsmp = {
        APIC_INIT("bigsmp", probe_bigsmp),
-       GENAPIC_PHYS
+       .int_delivery_mode = dest_Fixed,
+       .int_dest_mode = 0, /* physical delivery */
+       .init_apic_ldr = init_apic_ldr_phys,
+       .vector_allocation_cpumask = vector_allocation_cpumask_phys,
+       .cpu_mask_to_apicid = cpu_mask_to_apicid_phys,
+       .send_IPI_mask = send_IPI_mask_phys,
+       .send_IPI_self = send_IPI_self_legacy
 };
diff --git a/xen/arch/x86/genapic/default.c b/xen/arch/x86/genapic/default.c
index a968836a18..59c79afdb8 100644
--- a/xen/arch/x86/genapic/default.c
+++ b/xen/arch/x86/genapic/default.c
@@ -16,5 +16,11 @@
 /* should be called last. */
 const struct genapic __initconst_cf_clobber apic_default = {
        APIC_INIT("default", NULL),
-       GENAPIC_FLAT
+       .int_delivery_mode = dest_Fixed,
+       .int_dest_mode = 0, /* physical delivery */
+       .init_apic_ldr = init_apic_ldr_flat,
+       .vector_allocation_cpumask = vector_allocation_cpumask_phys,
+       .cpu_mask_to_apicid = cpu_mask_to_apicid_phys,
+       .send_IPI_mask = send_IPI_mask_flat,
+       .send_IPI_self = send_IPI_self_legacy
 };
diff --git a/xen/arch/x86/genapic/delivery.c b/xen/arch/x86/genapic/delivery.c
index d1f99bf683..3def78f380 100644
--- a/xen/arch/x86/genapic/delivery.c
+++ b/xen/arch/x86/genapic/delivery.c
@@ -19,16 +19,6 @@ void cf_check init_apic_ldr_flat(void)
        apic_write(APIC_LDR, val);
 }
 
-const cpumask_t *cf_check vector_allocation_cpumask_flat(int cpu)
-{
-       return &cpu_online_map;
-} 
-
-unsigned int cf_check cpu_mask_to_apicid_flat(const cpumask_t *cpumask)
-{
-       return cpumask_bits(cpumask)[0]&0xFF;
-}
-
 /*
  * PHYSICAL DELIVERY MODE (unicast to physical APIC IDs).
  */
diff --git a/xen/arch/x86/include/asm/genapic.h 
b/xen/arch/x86/include/asm/genapic.h
index a694371c6d..4d39fb9a24 100644
--- a/xen/arch/x86/include/asm/genapic.h
+++ b/xen/arch/x86/include/asm/genapic.h
@@ -44,29 +44,11 @@ extern const struct genapic apic_bigsmp;
 void cf_check send_IPI_self_legacy(uint8_t vector);
 
 void cf_check init_apic_ldr_flat(void);
-unsigned int cf_check cpu_mask_to_apicid_flat(const cpumask_t *cpumask);
 void cf_check send_IPI_mask_flat(const cpumask_t *cpumask, int vector);
-const cpumask_t *cf_check vector_allocation_cpumask_flat(int cpu);
-#define GENAPIC_FLAT \
-       .int_delivery_mode = dest_LowestPrio, \
-       .int_dest_mode = 1 /* logical delivery */, \
-       .init_apic_ldr = init_apic_ldr_flat, \
-       .vector_allocation_cpumask = vector_allocation_cpumask_flat, \
-       .cpu_mask_to_apicid = cpu_mask_to_apicid_flat, \
-       .send_IPI_mask = send_IPI_mask_flat, \
-       .send_IPI_self = send_IPI_self_legacy
 
 void cf_check init_apic_ldr_phys(void);
 unsigned int cf_check cpu_mask_to_apicid_phys(const cpumask_t *cpumask);
 void cf_check send_IPI_mask_phys(const cpumask_t *mask, int vector);
 const cpumask_t *cf_check vector_allocation_cpumask_phys(int cpu);
-#define GENAPIC_PHYS \
-       .int_delivery_mode = dest_Fixed, \
-       .int_dest_mode = 0 /* physical delivery */, \
-       .init_apic_ldr = init_apic_ldr_phys, \
-       .vector_allocation_cpumask = vector_allocation_cpumask_phys, \
-       .cpu_mask_to_apicid = cpu_mask_to_apicid_phys, \
-       .send_IPI_mask = send_IPI_mask_phys, \
-       .send_IPI_self = send_IPI_self_legacy
 
 #endif
--
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