From: David Woodhouse <dwmw2@infradead.org>
To: x86@kernel.org
Cc: kvm <kvm@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-hyperv@vger.kernel.org
Subject: [PATCH v2 1/8] x86/apic: Fix x2apic enablement without interrupt remapping
Date: Fri, 9 Oct 2020 11:46:09 +0100 [thread overview]
Message-ID: <20201009104616.1314746-2-dwmw2@infradead.org> (raw)
In-Reply-To: <20201009104616.1314746-1-dwmw2@infradead.org>
From: David Woodhouse <dwmw@amazon.co.uk>
Currently, Linux as a hypervisor guest will enable x2apic only if there
are no CPUs present at boot time with an APIC ID above 255.
Hotplugging a CPU later with a higher APIC ID would result in a CPU
which cannot be targeted by external interrupts.
Add a filter in x2apic_apic_id_valid() which can be used to prevent
such CPUs from coming online, and allow x2apic to be enabled even if
they are present at boot time.
Fixes: ce69a784504 ("x86/apic: Enable x2APIC without interrupt remapping under KVM")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
arch/x86/include/asm/apic.h | 1 +
arch/x86/kernel/apic/apic.c | 14 ++++++++------
arch/x86/kernel/apic/x2apic_phys.c | 9 +++++++++
3 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 1c129abb7f09..b0fd204e0023 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -259,6 +259,7 @@ static inline u64 native_x2apic_icr_read(void)
extern int x2apic_mode;
extern int x2apic_phys;
+extern void __init x2apic_set_max_apicid(u32 apicid);
extern void __init check_x2apic(void);
extern void x2apic_setup(void);
static inline int x2apic_enabled(void)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index b3eef1d5c903..113f6ca7b828 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1841,20 +1841,22 @@ static __init void try_to_enable_x2apic(int remap_mode)
return;
if (remap_mode != IRQ_REMAP_X2APIC_MODE) {
- /* IR is required if there is APIC ID > 255 even when running
- * under KVM
+ /*
+ * Using X2APIC without IR is not architecturally supported
+ * on bare metal but may be supported in guests.
*/
- if (max_physical_apicid > 255 ||
- !x86_init.hyper.x2apic_available()) {
+ if (!x86_init.hyper.x2apic_available()) {
pr_info("x2apic: IRQ remapping doesn't support X2APIC mode\n");
x2apic_disable();
return;
}
/*
- * without IR all CPUs can be addressed by IOAPIC/MSI
- * only in physical mode
+ * Without IR, all CPUs can be addressed by IOAPIC/MSI only
+ * in physical mode, and CPUs with an APIC ID that cannnot
+ * be addressed must not be brought online.
*/
+ x2apic_set_max_apicid(255);
x2apic_phys = 1;
}
x2apic_enable();
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index bc9693841353..e14eae6d6ea7 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -8,6 +8,12 @@
int x2apic_phys;
static struct apic apic_x2apic_phys;
+static u32 x2apic_max_apicid __ro_after_init;
+
+void __init x2apic_set_max_apicid(u32 apicid)
+{
+ x2apic_max_apicid = apicid;
+}
static int __init set_x2apic_phys_mode(char *arg)
{
@@ -98,6 +104,9 @@ static int x2apic_phys_probe(void)
/* Common x2apic functions, also used by x2apic_cluster */
int x2apic_apic_id_valid(u32 apicid)
{
+ if (x2apic_max_apicid && apicid > x2apic_max_apicid)
+ return 0;
+
return 1;
}
--
2.26.2
next prev parent reply other threads:[~2020-10-09 10:47 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <803bb6b2212e65c568c84ff6882c2aa8a0ee03d5.camel@infradead.org>
2020-10-09 10:46 ` [PATCH v2 0/8] Fix x2apic enablement and allow up to 32768 CPUs without IR where supported David Woodhouse
2020-10-09 10:46 ` David Woodhouse [this message]
2020-10-09 10:46 ` [PATCH v2 2/8] x86/msi: Only use high bits of MSI address for DMAR unit David Woodhouse
2020-10-09 10:46 ` [PATCH v2 3/8] x86/apic: Always provide irq_compose_msi_msg() method for vector domain David Woodhouse
2020-10-09 10:46 ` [PATCH v2 4/8] x86/ioapic: Handle Extended Destination ID field in RTE David Woodhouse
2020-10-09 10:46 ` [PATCH v2 5/8] x86/apic: Support 15 bits of APIC ID in MSI where available David Woodhouse
2020-10-09 10:46 ` [PATCH v2 6/8] x86/kvm: Add KVM_FEATURE_MSI_EXT_DEST_ID David Woodhouse
2020-10-09 10:46 ` [PATCH v2 7/8] x86/hpet: Move MSI support into hpet.c David Woodhouse
2020-10-09 10:46 ` [PATCH v2 8/8] x86/ioapic: Generate RTE directly from parent irqchip's MSI message David Woodhouse
2020-10-22 21:43 ` Thomas Gleixner
2020-10-22 22:10 ` Thomas Gleixner
2020-10-23 17:04 ` David Woodhouse
2020-10-23 10:10 ` David Woodhouse
2020-10-23 21:28 ` Thomas Gleixner
2020-10-24 8:26 ` David Woodhouse
2020-10-24 8:41 ` David Woodhouse
2020-10-24 9:13 ` Paolo Bonzini
2020-10-24 10:13 ` David Woodhouse
2020-10-24 12:44 ` David Woodhouse
2020-10-24 21:35 ` [PATCH v3 00/35] Fix x2apic enablement and allow more CPUs, clean up I/OAPIC and MSI bitfields David Woodhouse
2020-10-24 21:35 ` [PATCH v3 01/35] x86/apic: Fix x2apic enablement without interrupt remapping David Woodhouse
2020-10-24 21:35 ` [PATCH v3 02/35] x86/msi: Only use high bits of MSI address for DMAR unit David Woodhouse
2020-10-24 21:35 ` [PATCH v3 03/35] x86/apic/uv: Fix inconsistent destination mode David Woodhouse
2020-10-24 21:35 ` [PATCH v3 04/35] x86/devicetree: Fix the ioapic interrupt type table David Woodhouse
2020-10-24 21:35 ` [PATCH v3 05/35] x86/apic: Cleanup delivery mode defines David Woodhouse
2020-10-24 21:35 ` [PATCH v3 06/35] x86/apic: Replace pointless apic::dest_logical usage David Woodhouse
2020-10-24 21:35 ` [PATCH v3 07/35] x86/apic: Get rid of apic::dest_logical David Woodhouse
2020-10-24 21:35 ` [PATCH v3 08/35] x86/apic: Cleanup destination mode David Woodhouse
2020-10-24 21:35 ` [PATCH v3 09/35] x86/apic: Always provide irq_compose_msi_msg() method for vector domain David Woodhouse
2020-10-24 21:35 ` [PATCH v3 10/35] x86/hpet: Move MSI support into hpet.c David Woodhouse
2020-10-24 21:35 ` [PATCH v3 11/35] genirq/msi: Allow shadow declarations of msi_msg::$member David Woodhouse
2020-10-24 21:35 ` [PATCH v3 12/35] x86/msi: Provide msi message shadow structs David Woodhouse
2022-04-06 8:36 ` Reto Buerki
2022-04-06 8:36 ` [PATCH] x86/msi: Fix msi message data shadow struct Reto Buerki
2022-04-06 22:11 ` Thomas Gleixner
2022-04-07 11:06 ` Reto Buerki
2022-04-06 22:07 ` [PATCH v3 12/35] x86/msi: Provide msi message shadow structs Thomas Gleixner
2020-10-24 21:35 ` [PATCH v3 13/35] iommu/intel: Use msi_msg " David Woodhouse
2020-10-24 21:35 ` [PATCH v3 14/35] iommu/amd: " David Woodhouse
2020-10-24 21:35 ` [PATCH v3 15/35] PCI: vmd: " David Woodhouse
2020-10-28 20:49 ` Kees Cook
2020-10-28 21:13 ` Thomas Gleixner
2020-10-28 23:22 ` Kees Cook
2020-10-24 21:35 ` [PATCH v3 16/35] x86/kvm: " David Woodhouse
2020-10-24 21:35 ` [PATCH v3 17/35] x86/pci/xen: " David Woodhouse
2020-10-25 9:49 ` David Laight
2020-10-25 10:26 ` David Woodhouse
2020-10-25 13:20 ` David Laight
2020-10-24 21:35 ` [PATCH v3 18/35] x86/msi: Remove msidef.h David Woodhouse
2020-10-24 21:35 ` [PATCH v3 19/35] x86/io_apic: Cleanup trigger/polarity helpers David Woodhouse
2020-11-10 6:31 ` Qian Cai
2020-11-10 8:59 ` David Woodhouse
2020-11-10 16:26 ` Paolo Bonzini
2020-10-24 21:35 ` [PATCH v3 20/35] x86/ioapic: Cleanup IO/APIC route entry structs David Woodhouse
2020-10-24 21:35 ` [PATCH v3 21/35] x86/ioapic: Generate RTE directly from parent irqchip's MSI message David Woodhouse
2020-10-24 21:35 ` [PATCH v3 22/35] genirq/irqdomain: Implement get_name() method on irqchip fwnodes David Woodhouse
2020-10-25 9:41 ` Marc Zyngier
2020-10-24 21:35 ` [PATCH v3 23/35] x86/apic: Add select() method on vector irqdomain David Woodhouse
2020-10-24 21:35 ` [PATCH v3 24/35] iommu/amd: Implement select() method on remapping irqdomain David Woodhouse
2020-10-24 21:35 ` [PATCH v3 25/35] iommu/vt-d: " David Woodhouse
2020-10-24 21:35 ` [PATCH v3 26/35] iommu/hyper-v: " David Woodhouse
2020-10-24 21:35 ` [PATCH v3 27/35] x86/hpet: Use irq_find_matching_fwspec() to find " David Woodhouse
2020-10-24 21:35 ` [PATCH v3 28/35] x86/ioapic: " David Woodhouse
2020-10-24 21:35 ` [PATCH v3 29/35] x86: Kill all traces of irq_remapping_get_irq_domain() David Woodhouse
2020-10-24 21:35 ` [PATCH v3 30/35] iommu/vt-d: Simplify intel_irq_remapping_select() David Woodhouse
2020-10-24 21:35 ` [PATCH v3 31/35] x86/ioapic: Handle Extended Destination ID field in RTE David Woodhouse
2020-10-24 21:35 ` [PATCH v3 32/35] x86/apic: Support 15 bits of APIC ID in MSI where available David Woodhouse
2020-10-24 21:35 ` [PATCH v3 33/35] iommu/hyper-v: Disable IRQ pseudo-remapping if 15 bit APIC IDs are available David Woodhouse
2020-10-24 21:35 ` [PATCH v3 34/35] x86/kvm: Reserve KVM_FEATURE_MSI_EXT_DEST_ID David Woodhouse
2020-10-24 21:35 ` [PATCH v3 35/35] x86/kvm: Enable 15-bit extension when KVM_FEATURE_MSI_EXT_DEST_ID detected David Woodhouse
2020-10-25 8:12 ` [PATCH v3 00/35] Fix x2apic enablement and allow more CPUs, clean up I/OAPIC and MSI bitfields David Woodhouse
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