From: Saurabh Sengar ssengar@linux.microsoft.com
[ Upstream commit 2b4b90e053a29057fb05ba81acce26bddce8d404 ]
Currently, the secondary CPUs in Hyper-V VTL context lack support for parallel startup. Therefore, relying on the single initial_stack fetched from the current task structure suffices for all vCPUs.
However, common initial_stack risks stack corruption when parallel startup is enabled. In order to facilitate parallel startup, use the initial_stack from the per CPU idle thread instead of the current task.
Fixes: 3be1bc2fe9d2 ("x86/hyperv: VTL support for Hyper-V") Signed-off-by: Saurabh Sengar ssengar@linux.microsoft.com Reviewed-by: Michael Kelley mhklinux@outlook.com Link: https://lore.kernel.org/r/1709452896-13342-1-git-send-email-ssengar@linux.mi... Signed-off-by: Wei Liu wei.liu@kernel.org Message-ID: 1709452896-13342-1-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/hyperv/hv_vtl.c | 19 +++++++++++++++---- drivers/hv/Kconfig | 1 + 2 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c index 53b309d41b3b9..c2f78fabc865b 100644 --- a/arch/x86/hyperv/hv_vtl.c +++ b/arch/x86/hyperv/hv_vtl.c @@ -12,6 +12,7 @@ #include <asm/i8259.h> #include <asm/mshyperv.h> #include <asm/realmode.h> +#include <../kernel/smpboot.h>
extern struct boot_params boot_params; static struct real_mode_header hv_vtl_real_mode_header; @@ -64,7 +65,7 @@ static void hv_vtl_ap_entry(void) ((secondary_startup_64_fn)secondary_startup_64)(&boot_params, &boot_params); }
-static int hv_vtl_bringup_vcpu(u32 target_vp_index, u64 eip_ignored) +static int hv_vtl_bringup_vcpu(u32 target_vp_index, int cpu, u64 eip_ignored) { u64 status; int ret = 0; @@ -78,7 +79,9 @@ static int hv_vtl_bringup_vcpu(u32 target_vp_index, u64 eip_ignored) struct ldttss_desc *ldt; struct desc_struct *gdt;
- u64 rsp = current->thread.sp; + struct task_struct *idle = idle_thread_get(cpu); + u64 rsp = (unsigned long)idle->thread.sp; + u64 rip = (u64)&hv_vtl_ap_entry;
native_store_gdt(&gdt_ptr); @@ -205,7 +208,15 @@ static int hv_vtl_apicid_to_vp_id(u32 apic_id)
static int hv_vtl_wakeup_secondary_cpu(int apicid, unsigned long start_eip) { - int vp_id; + int vp_id, 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;
pr_debug("Bringing up CPU with APIC ID %d in VTL2...\n", apicid); vp_id = hv_vtl_apicid_to_vp_id(apicid); @@ -219,7 +230,7 @@ static int hv_vtl_wakeup_secondary_cpu(int apicid, unsigned long start_eip) return -EINVAL; }
- return hv_vtl_bringup_vcpu(vp_id, start_eip); + return hv_vtl_bringup_vcpu(vp_id, cpu, start_eip); }
int __init hv_vtl_early_init(void) diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig index 00242107d62e0..862c47b191afe 100644 --- a/drivers/hv/Kconfig +++ b/drivers/hv/Kconfig @@ -16,6 +16,7 @@ config HYPERV config HYPERV_VTL_MODE bool "Enable Linux to boot in VTL context" depends on X86_64 && HYPERV + depends on SMP default n help Virtual Secure Mode (VSM) is a set of hypervisor capabilities and