From 6130ab24d03e4df9dc4a2c94dce2582d2971c647 Mon Sep 17 00:00:00 2001 From: Xiaoyao Li Date: Wed, 30 Jul 2025 17:52:52 +0800 Subject: [PATCH] i386/cpu: Enable SMM cpu address space under KVM Kirill Martynov reported assertation in cpu_asidx_from_attrs() being hit when x86_cpu_dump_state() is called to dump the CPU state[*]. It happens when the CPU is in SMM and KVM emulation failure due to misbehaving guest. The root cause is that QEMU i386 never enables the SMM address space for cpu since KVM SMM support has been added. Enable the SMM cpu address space under KVM when the SMM is enabled for the x86machine. [*] https://lore.kernel.org/qemu-devel/20250523154431.506993-1-stdcalllevi@yandex-team.ru/ Reported-by: Kirill Martynov Reviewed-by: Zhao Liu Tested-by: Kirill Martynov Signed-off-by: Xiaoyao Li Link: https://lore.kernel.org/r/20250730095253.1833411-2-xiaoyao.li@intel.com Signed-off-by: Paolo Bonzini (cherry picked from commit 0516f4b70264b9710a25718d21bd35ef463c875e) Signed-off-by: Michael Tokarev --- system/physmem.c | 5 ----- target/i386/kvm/kvm-cpu.c | 10 ++++++++++ target/i386/kvm/kvm.c | 5 +++++ 3 files changed, 15 insertions(+), 5 deletions(-) diff --git a/system/physmem.c b/system/physmem.c index e5dd760e0bc..8705fadc01d 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -793,9 +793,6 @@ void cpu_address_space_init(CPUState *cpu, int asidx, cpu->as = as; } - /* KVM cannot currently support multiple address spaces. */ - assert(asidx == 0 || !kvm_enabled()); - if (!cpu->cpu_ases) { cpu->cpu_ases = g_new0(CPUAddressSpace, cpu->num_ases); cpu->cpu_ases_count = cpu->num_ases; @@ -818,8 +815,6 @@ void cpu_address_space_destroy(CPUState *cpu, int asidx) assert(cpu->cpu_ases); assert(asidx >= 0 && asidx < cpu->num_ases); - /* KVM cannot currently support multiple address spaces. */ - assert(asidx == 0 || !kvm_enabled()); cpuas = &cpu->cpu_ases[asidx]; if (tcg_enabled()) { diff --git a/target/i386/kvm/kvm-cpu.c b/target/i386/kvm/kvm-cpu.c index 89a79536594..1dc1ba9b486 100644 --- a/target/i386/kvm/kvm-cpu.c +++ b/target/i386/kvm/kvm-cpu.c @@ -13,6 +13,7 @@ #include "qapi/error.h" #include "system/system.h" #include "hw/boards.h" +#include "hw/i386/x86.h" #include "kvm_i386.h" #include "accel/accel-cpu-target.h" @@ -91,6 +92,15 @@ static bool kvm_cpu_realizefn(CPUState *cs, Error **errp) kvm_set_guest_phys_bits(cs); } + /* + * When SMM is enabled, there is 2 address spaces. Otherwise only 1. + * + * Only initialize address space 0 here, the second one for SMM is + * initialized at register_smram_listener() after machine init done. + */ + cs->num_ases = x86_machine_is_smm_enabled(X86_MACHINE(current_machine)) ? 2 : 1; + cpu_address_space_init(cs, 0, "cpu-memory", cs->memory); + return true; } diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 369626f8c8d..47fb5c673c8 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -2704,6 +2704,7 @@ static MemoryRegion smram_as_mem; static void register_smram_listener(Notifier *n, void *unused) { + CPUState *cpu; MemoryRegion *smram = (MemoryRegion *) object_resolve_path("/machine/smram", NULL); @@ -2728,6 +2729,10 @@ static void register_smram_listener(Notifier *n, void *unused) address_space_init(&smram_address_space, &smram_as_root, "KVM-SMRAM"); kvm_memory_listener_register(kvm_state, &smram_listener, &smram_address_space, 1, "kvm-smram"); + + CPU_FOREACH(cpu) { + cpu_address_space_init(cpu, 1, "cpu-smm", &smram_as_root); + } } static void *kvm_msr_energy_thread(void *data) -- 2.47.3