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Message-ID: <20220711152230.17749-1-jane.malalane@citrix.com>
Date: Mon, 11 Jul 2022 16:22:30 +0100
From: Jane Malalane <jane.malalane@...rix.com>
To: LKML <linux-kernel@...r.kernel.org>
CC: Jane Malalane <jane.malalane@...rix.com>,
Juergen Gross <jgross@...e.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>, <x86@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Stefano Stabellini <sstabellini@...nel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
Maximilian Heyne <mheyne@...zon.de>,
"Jan Beulich" <jbeulich@...e.com>,
Colin Ian King <colin.king@...el.com>,
<xen-devel@...ts.xenproject.org>
Subject: [PATCH] x86/xen: Add support for HVMOP_set_evtchn_upcall_vector
Implement support for the HVMOP_set_evtchn_upcall_vector hypercall in
order to set the per-vCPU event channel vector callback on Linux and
use it in preference of HVM_PARAM_CALLBACK_IRQ.
If the per-VCPU vector setup is successful on BSP, use this method
for the APs. If not, fallback to the global vector-type callback.
Also register callback_irq at per-vCPU event channel setup to trick
toolstack to think the domain is enlightened.
Suggested-by: "Roger Pau Monné" <roger.pau@...rix.com>
Signed-off-by: Jane Malalane <jane.malalane@...rix.com>
---
CC: Juergen Gross <jgross@...e.com>
CC: Boris Ostrovsky <boris.ostrovsky@...cle.com>
CC: Thomas Gleixner <tglx@...utronix.de>
CC: Ingo Molnar <mingo@...hat.com>
CC: Borislav Petkov <bp@...en8.de>
CC: Dave Hansen <dave.hansen@...ux.intel.com>
CC: x86@...nel.org
CC: "H. Peter Anvin" <hpa@...or.com>
CC: Stefano Stabellini <sstabellini@...nel.org>
CC: Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>
CC: Jane Malalane <jane.malalane@...rix.com>
CC: Maximilian Heyne <mheyne@...zon.de>
CC: Jan Beulich <jbeulich@...e.com>
CC: Colin Ian King <colin.king@...el.com>
CC: xen-devel@...ts.xenproject.org
---
arch/x86/include/asm/xen/cpuid.h | 2 ++
arch/x86/include/asm/xen/events.h | 1 +
arch/x86/xen/enlighten_hvm.c | 19 +++++++++++++++++--
arch/x86/xen/suspend_hvm.c | 20 +++++++++++++++++++-
drivers/xen/events/events_base.c | 32 ++++++++++++++++++++++++++++----
include/xen/interface/hvm/hvm_op.h | 15 +++++++++++++++
6 files changed, 82 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/xen/cpuid.h b/arch/x86/include/asm/xen/cpuid.h
index 78e667a31d6c..6daa9b0c8d11 100644
--- a/arch/x86/include/asm/xen/cpuid.h
+++ b/arch/x86/include/asm/xen/cpuid.h
@@ -107,6 +107,8 @@
* ID field from 8 to 15 bits, allowing to target APIC IDs up 32768.
*/
#define XEN_HVM_CPUID_EXT_DEST_ID (1u << 5)
+/* Per-vCPU event channel upcalls */
+#define XEN_HVM_CPUID_UPCALL_VECTOR (1u << 6)
/*
* Leaf 6 (0x40000x05)
diff --git a/arch/x86/include/asm/xen/events.h b/arch/x86/include/asm/xen/events.h
index 068d9b067c83..b2d86c761bf8 100644
--- a/arch/x86/include/asm/xen/events.h
+++ b/arch/x86/include/asm/xen/events.h
@@ -34,4 +34,5 @@ static inline bool xen_support_evtchn_rebind(void)
return (!xen_hvm_domain() || xen_have_vector_callback);
}
+extern bool xen_ack_upcall;
#endif /* _ASM_X86_XEN_EVENTS_H */
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 8b71b1dd7639..847d1da46ff7 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -7,6 +7,7 @@
#include <xen/features.h>
#include <xen/events.h>
+#include <xen/interface/hvm/hvm_op.h>
#include <xen/interface/memory.h>
#include <asm/apic.h>
@@ -30,6 +31,9 @@
static unsigned long shared_info_pfn;
+__ro_after_init bool xen_ack_upcall;
+EXPORT_SYMBOL_GPL(xen_ack_upcall);
+
void xen_hvm_init_shared_info(void)
{
struct xen_add_to_physmap xatp;
@@ -125,6 +129,9 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
{
struct pt_regs *old_regs = set_irq_regs(regs);
+ if (xen_ack_upcall)
+ ack_APIC_irq();
+
inc_irq_stat(irq_hv_callback_count);
xen_hvm_evtchn_do_upcall();
@@ -168,6 +175,15 @@ static int xen_cpu_up_prepare_hvm(unsigned int cpu)
if (!xen_have_vector_callback)
return 0;
+ if (xen_ack_upcall) {
+ xen_hvm_evtchn_upcall_vector_t op = {
+ .vector = HYPERVISOR_CALLBACK_VECTOR,
+ .vcpu = per_cpu(xen_vcpu_id, cpu),
+ };
+
+ BUG_ON(HYPERVISOR_hvm_op(HVMOP_set_evtchn_upcall_vector, &op));
+ }
+
if (xen_feature(XENFEAT_hvm_safe_pvclock))
xen_setup_timer(cpu);
@@ -211,8 +227,7 @@ static void __init xen_hvm_guest_init(void)
xen_panic_handler_init();
- if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
- xen_have_vector_callback = 1;
+ xen_have_vector_callback = !no_vector_callback;
xen_hvm_smp_init();
WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_hvm, xen_cpu_dead_hvm));
diff --git a/arch/x86/xen/suspend_hvm.c b/arch/x86/xen/suspend_hvm.c
index 9d548b0c772f..be66e027ef28 100644
--- a/arch/x86/xen/suspend_hvm.c
+++ b/arch/x86/xen/suspend_hvm.c
@@ -5,6 +5,7 @@
#include <xen/hvm.h>
#include <xen/features.h>
#include <xen/interface/features.h>
+#include <xen/events.h>
#include "xen-ops.h"
@@ -14,6 +15,23 @@ void xen_hvm_post_suspend(int suspend_cancelled)
xen_hvm_init_shared_info();
xen_vcpu_restore();
}
- xen_setup_callback_vector();
+ if (xen_ack_upcall) {
+ unsigned int cpu;
+
+ for_each_online_cpu(cpu) {
+ xen_hvm_evtchn_upcall_vector_t op = {
+ .vector = HYPERVISOR_CALLBACK_VECTOR,
+ .vcpu = per_cpu(xen_vcpu_id, cpu),
+ };
+
+ BUG_ON(HYPERVISOR_hvm_op(HVMOP_set_evtchn_upcall_vector,
+ &op));
+ /* Trick toolstack to think we are enlightened. */
+ if (!cpu)
+ BUG_ON(xen_set_callback_via(1));
+ }
+ } else {
+ xen_setup_callback_vector();
+ }
xen_unplug_emulated_devices();
}
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 46d9295d9a6e..a2420b66e735 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -48,6 +48,7 @@
#include <asm/xen/pci.h>
#endif
#include <asm/sync_bitops.h>
+#include <asm/xen/cpuid.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
#include <xen/page.h>
@@ -2200,6 +2201,29 @@ void xen_setup_callback_vector(void)
}
}
+/* Setup per-vCPU vector-type callbacks and trick toolstack to think
+ * we are enlightened. If this setup is unavailable, fallback to the
+ * global vector-type callback. */
+static __init void xen_setup_upcall_vector(void)
+{
+ xen_hvm_evtchn_upcall_vector_t op = {
+ .vector = HYPERVISOR_CALLBACK_VECTOR,
+ .vcpu = per_cpu(xen_vcpu_id, 0),
+ };
+
+ if (!xen_have_vector_callback)
+ return;
+
+ if ((cpuid_eax(xen_cpuid_base() + 4) & XEN_HVM_CPUID_UPCALL_VECTOR) &&
+ !HYPERVISOR_hvm_op(HVMOP_set_evtchn_upcall_vector, &op) &&
+ !xen_set_callback_via(1))
+ xen_ack_upcall = true;
+ else if (xen_feature(XENFEAT_hvm_callback_vector))
+ xen_setup_callback_vector();
+ else
+ xen_have_vector_callback = 0;
+}
+
static __init void xen_alloc_callback_vector(void)
{
if (!xen_have_vector_callback)
@@ -2210,6 +2234,7 @@ static __init void xen_alloc_callback_vector(void)
}
#else
void xen_setup_callback_vector(void) {}
+static inline void xen_setup_upcall_vector(void) {}
static inline void xen_alloc_callback_vector(void) {}
#endif
@@ -2271,10 +2296,9 @@ void __init xen_init_IRQ(void)
if (xen_initial_domain())
pci_xen_initial_domain();
}
- if (xen_feature(XENFEAT_hvm_callback_vector)) {
- xen_setup_callback_vector();
- xen_alloc_callback_vector();
- }
+ xen_setup_upcall_vector();
+ xen_alloc_callback_vector();
+
if (xen_hvm_domain()) {
native_init_IRQ();
diff --git a/include/xen/interface/hvm/hvm_op.h b/include/xen/interface/hvm/hvm_op.h
index f3097e79bb03..e714d8b6ef89 100644
--- a/include/xen/interface/hvm/hvm_op.h
+++ b/include/xen/interface/hvm/hvm_op.h
@@ -46,4 +46,19 @@ struct xen_hvm_get_mem_type {
};
DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_get_mem_type);
+/*
+ * HVMOP_set_evtchn_upcall_vector: Set a <vector> that should be used for event
+ * channel upcalls on the specified <vcpu>. If set,
+ * this vector will be used in preference to the
+ * domain global callback via (see
+ * HVM_PARAM_CALLBACK_IRQ).
+ */
+#define HVMOP_set_evtchn_upcall_vector 23
+struct xen_hvm_evtchn_upcall_vector {
+ uint32_t vcpu;
+ uint8_t vector;
+};
+typedef struct xen_hvm_evtchn_upcall_vector xen_hvm_evtchn_upcall_vector_t;
+DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_evtchn_upcall_vector_t);
+
#endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */
--
2.11.0
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