diff mbox series

[hyperv-next,2/2] arch/x86: Provide the CPU number in the wakeup AP callback

Message ID 20250507182227.7421-3-romank@linux.microsoft.com
State New
Headers show
Series arch/x86, x86/hyperv: Few fixes for the AP startup | expand

Commit Message

Roman Kisel May 7, 2025, 6:22 p.m. UTC
When starting APs, confidential guests and paravisor guests
need to know the CPU number, and the pattern of using the linear
search has emerged in several places. With N processors that leads
to the O(N^2) time complexity.

Provide the CPU number in the AP wake up callback so that one can
get the CPU number in constant time.

Suggested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
---
 arch/x86/coco/sev/core.c             | 13 ++-----------
 arch/x86/hyperv/hv_vtl.c             | 12 ++----------
 arch/x86/hyperv/ivm.c                | 15 ++-------------
 arch/x86/include/asm/apic.h          |  8 ++++----
 arch/x86/include/asm/mshyperv.h      |  5 +++--
 arch/x86/kernel/acpi/madt_wakeup.c   |  2 +-
 arch/x86/kernel/apic/apic_noop.c     |  8 +++++++-
 arch/x86/kernel/apic/apic_numachip.c |  2 +-
 arch/x86/kernel/apic/x2apic_uv_x.c   |  2 +-
 arch/x86/kernel/smpboot.c            | 10 +++++-----
 10 files changed, 28 insertions(+), 49 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index b0c1a7a57497..7780d55d1833 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -1177,7 +1177,7 @@  static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa, int apic_id)
 		free_page((unsigned long)vmsa);
 }
 
-static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
+static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip, unsigned int cpu)
 {
 	struct sev_es_save_area *cur_vmsa, *vmsa;
 	struct ghcb_state state;
@@ -1185,7 +1185,7 @@  static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
 	unsigned long flags;
 	struct ghcb *ghcb;
 	u8 sipi_vector;
-	int cpu, ret;
+	int ret;
 	u64 cr4;
 
 	/*
@@ -1206,15 +1206,6 @@  static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
 
 	/* Override start_ip with known protected guest start IP */
 	start_ip = real_mode_header->sev_es_trampoline_start;
-
-	/* Find the logical CPU for the APIC ID */
-	for_each_present_cpu(cpu) {
-		if (arch_match_cpu_phys_id(cpu, apic_id))
-			break;
-	}
-	if (cpu >= nr_cpu_ids)
-		return -EINVAL;
-
 	cur_vmsa = per_cpu(sev_vmsa, cpu);
 
 	/*
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 2f32ac1ae40e..3d149a2ca4c8 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -211,17 +211,9 @@  static int hv_vtl_bringup_vcpu(u32 target_vp_index, int cpu, u64 eip_ignored)
 	return ret;
 }
 
-static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip)
+static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip, unsigned int cpu)
 {
-	int vp_index, cpu;
-
-	/* Find the logical CPU for the APIC ID */
-	for_each_present_cpu(cpu) {
-		if (arch_match_cpu_phys_id(cpu, apicid))
-			break;
-	}
-	if (cpu >= nr_cpu_ids)
-		return -EINVAL;
+	int vp_index;
 
 	pr_debug("Bringing up CPU with APIC ID %d in VTL2...\n", apicid);
 	vp_index = hv_apicid_to_vp_index(apicid);
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 0cc239cdb4da..e21557b24d19 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -289,7 +289,7 @@  static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
 		free_page((unsigned long)vmsa);
 }
 
-int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip)
+int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip, unsigned int cpu)
 {
 	struct sev_es_save_area *vmsa = (struct sev_es_save_area *)
 		__get_free_page(GFP_KERNEL | __GFP_ZERO);
@@ -298,7 +298,7 @@  int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip)
 	u64 ret, retry = 5;
 	struct hv_enable_vp_vtl *start_vp_input;
 	unsigned long flags;
-	int cpu, vp_index;
+	int vp_index;
 
 	if (!vmsa)
 		return -ENOMEM;
@@ -308,17 +308,6 @@  int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip)
 	if (vp_index < 0 || vp_index > ms_hyperv.max_vp_index)
 		return -EINVAL;
 
-	/*
-	 * Find the Linux CPU number for addressing the per-CPU data, and it
-	 * might not be the same as APIC ID.
-	 */
-	for_each_present_cpu(cpu) {
-		if (arch_match_cpu_phys_id(cpu, apic_id))
-			break;
-	}
-	if (cpu >= nr_cpu_ids)
-		return -EINVAL;
-
 	native_store_gdt(&gdtr);
 
 	vmsa->gdtr.base = gdtr.address;
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index c903d358405d..eaf43d446203 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -313,9 +313,9 @@  struct apic {
 	u32	(*get_apic_id)(u32 id);
 
 	/* wakeup_secondary_cpu */
-	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip);
+	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip, unsigned int cpu);
 	/* wakeup secondary CPU using 64-bit wakeup point */
-	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip);
+	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip, unsigned int cpu);
 
 	char	*name;
 };
@@ -333,8 +333,8 @@  struct apic_override {
 	void	(*send_IPI_self)(int vector);
 	u64	(*icr_read)(void);
 	void	(*icr_write)(u32 low, u32 high);
-	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip);
-	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip);
+	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip, unsigned int cpu);
+	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip, unsigned int cpu);
 };
 
 /*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 0b9a3a307d06..5ec92e3e2e37 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -268,11 +268,12 @@  int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 bool hv_ghcb_negotiate_protocol(void);
 void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason);
-int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip);
+int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip, unsigned int cpu);
 #else
 static inline bool hv_ghcb_negotiate_protocol(void) { return false; }
 static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
-static inline int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip) { return 0; }
+static inline int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip,
+		unsigned int cpu) { return 0; }
 #endif
 
 #if defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST)
diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c
index f36f28405dcc..6d7603511f52 100644
--- a/arch/x86/kernel/acpi/madt_wakeup.c
+++ b/arch/x86/kernel/acpi/madt_wakeup.c
@@ -126,7 +126,7 @@  static int __init acpi_mp_setup_reset(u64 reset_vector)
 	return 0;
 }
 
-static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip)
+static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip, unsigned int cpu)
 {
 	if (!acpi_mp_wake_mailbox_paddr) {
 		pr_warn_once("No MADT mailbox: cannot bringup secondary CPUs. Booting with kexec?\n");
diff --git a/arch/x86/kernel/apic/apic_noop.c b/arch/x86/kernel/apic/apic_noop.c
index b5bb7a2e8340..58abb941c45b 100644
--- a/arch/x86/kernel/apic/apic_noop.c
+++ b/arch/x86/kernel/apic/apic_noop.c
@@ -27,7 +27,13 @@  static void noop_send_IPI_allbutself(int vector) { }
 static void noop_send_IPI_all(int vector) { }
 static void noop_send_IPI_self(int vector) { }
 static void noop_apic_icr_write(u32 low, u32 id) { }
-static int noop_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip) { return -1; }
+
+static int noop_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip,
+	unsigned int cpu)
+{
+	return -1;
+}
+
 static u64 noop_apic_icr_read(void) { return 0; }
 static u32 noop_get_apic_id(u32 apicid) { return 0; }
 static void noop_apic_eoi(void) { }
diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c
index 16410f087b7a..333536b89bde 100644
--- a/arch/x86/kernel/apic/apic_numachip.c
+++ b/arch/x86/kernel/apic/apic_numachip.c
@@ -56,7 +56,7 @@  static void numachip2_apic_icr_write(int apicid, unsigned int val)
 	numachip2_write32_lcsr(NUMACHIP2_APIC_ICR, (apicid << 12) | val);
 }
 
-static int numachip_wakeup_secondary(u32 phys_apicid, unsigned long start_rip)
+static int numachip_wakeup_secondary(u32 phys_apicid, unsigned long start_rip, unsigned int cpu)
 {
 	numachip_apic_icr_write(phys_apicid, APIC_DM_INIT);
 	numachip_apic_icr_write(phys_apicid, APIC_DM_STARTUP |
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 7fef504ca508..15209f220e1f 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -667,7 +667,7 @@  static __init void build_uv_gr_table(void)
 	}
 }
 
-static int uv_wakeup_secondary(u32 phys_apicid, unsigned long start_rip)
+static int uv_wakeup_secondary(u32 phys_apicid, unsigned long start_rip, unsigned int cpu)
 {
 	unsigned long val;
 	int pnode;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index d6cf1e23c2a3..d52e9238e9fd 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -695,7 +695,7 @@  static void send_init_sequence(u32 phys_apicid)
 /*
  * Wake up AP by INIT, INIT, STARTUP sequence.
  */
-static int wakeup_secondary_cpu_via_init(u32 phys_apicid, unsigned long start_eip)
+static int wakeup_secondary_cpu_via_init(u32 phys_apicid, unsigned long start_eip, unsigned int cpu)
 {
 	unsigned long send_status = 0, accept_status = 0;
 	int num_starts, j, maxlvt;
@@ -842,7 +842,7 @@  int common_cpu_up(unsigned int cpu, struct task_struct *idle)
  * Returns zero if startup was successfully sent, else error code from
  * ->wakeup_secondary_cpu.
  */
-static int do_boot_cpu(u32 apicid, int cpu, struct task_struct *idle)
+static int do_boot_cpu(u32 apicid, unsigned int cpu, struct task_struct *idle)
 {
 	unsigned long start_ip = real_mode_header->trampoline_start;
 	int ret;
@@ -896,11 +896,11 @@  static int do_boot_cpu(u32 apicid, int cpu, struct task_struct *idle)
 	 * - Use an INIT boot APIC message
 	 */
 	if (apic->wakeup_secondary_cpu_64)
-		ret = apic->wakeup_secondary_cpu_64(apicid, start_ip);
+		ret = apic->wakeup_secondary_cpu_64(apicid, start_ip, cpu);
 	else if (apic->wakeup_secondary_cpu)
-		ret = apic->wakeup_secondary_cpu(apicid, start_ip);
+		ret = apic->wakeup_secondary_cpu(apicid, start_ip, cpu);
 	else
-		ret = wakeup_secondary_cpu_via_init(apicid, start_ip);
+		ret = wakeup_secondary_cpu_via_init(apicid, start_ip, cpu);
 
 	/* If the wakeup mechanism failed, cleanup the warm reset vector */
 	if (ret)