| Message ID | 20240611032314.64076-1-xuchuangxclwt@bytedance.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] i386/cpu: fixup number of addressable IDs for processor cores in the physical package | expand |
On Tue, Jun 11, 2024 at 11:23:14AM +0800, Chuang Xu wrote: > Date: Tue, 11 Jun 2024 11:23:14 +0800 > From: Chuang Xu <xuchuangxclwt@bytedance.com> > Subject: [PATCH v3] i386/cpu: fixup number of addressable IDs for processor > cores in the physical package > X-Mailer: git-send-email 2.24.3 (Apple Git-128) > > When QEMU is started with: > -cpu host,host-cache-info=on,l3-cache=off \ > -smp 2,sockets=1,dies=1,cores=1,threads=2 > Guest can't acquire maximum number of addressable IDs for processor cores in > the physical package from CPUID[04H]. > > When creating a CPU topology of 1 core per package, host-cache-info only > uses the Host's addressable core IDs field (CPUID.04H.EAX[bits 31-26]), > resulting in a conflict (on the multicore Host) between the Guest core > topology information in this field and the Guest's actual cores number. > > Fix it by removing the unnecessary condition to cover 1 core per package > case. This is safe because cores_per_pkg will not be 0 and will be at > least 1. > > Fixes: d7caf13b5fcf ("x86: cpu: fixup number of addressable IDs for logical processors sharing cache") > Signed-off-by: Guixiong Wei <weiguixiong@bytedance.com> > Signed-off-by: Yipeng Yin <yinyipeng@bytedance.com> > Signed-off-by: Chuang Xu <xuchuangxclwt@bytedance.com> > --- > target/i386/cpu.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) Thanks! LGTM, Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Queued, thanks. Paolo
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index bc2dceb647..b68f7460db 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -6426,10 +6426,8 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, if (*eax & 31) { int host_vcpus_per_cache = 1 + ((*eax & 0x3FFC000) >> 14); - if (cores_per_pkg > 1) { - *eax &= ~0xFC000000; - *eax |= max_core_ids_in_package(&topo_info) << 26; - } + *eax &= ~0xFC000000; + *eax |= max_core_ids_in_package(&topo_info) << 26; if (host_vcpus_per_cache > threads_per_pkg) { *eax &= ~0x3FFC000;
When QEMU is started with: -cpu host,host-cache-info=on,l3-cache=off \ -smp 2,sockets=1,dies=1,cores=1,threads=2 Guest can't acquire maximum number of addressable IDs for processor cores in the physical package from CPUID[04H]. When creating a CPU topology of 1 core per package, host-cache-info only uses the Host's addressable core IDs field (CPUID.04H.EAX[bits 31-26]), resulting in a conflict (on the multicore Host) between the Guest core topology information in this field and the Guest's actual cores number. Fix it by removing the unnecessary condition to cover 1 core per package case. This is safe because cores_per_pkg will not be 0 and will be at least 1. Fixes: d7caf13b5fcf ("x86: cpu: fixup number of addressable IDs for logical processors sharing cache") Signed-off-by: Guixiong Wei <weiguixiong@bytedance.com> Signed-off-by: Yipeng Yin <yinyipeng@bytedance.com> Signed-off-by: Chuang Xu <xuchuangxclwt@bytedance.com> --- target/i386/cpu.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)