d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

vmm(4): Take steps towards multicore bhyve AMD support

Browse Source 
vmm's CPUID emulation presented Intel topology information to the guest, but
disabled AMD topology information and in some cases passed through garbage.
I.e., CPUID leaves 0x8000_001[de] were passed through to the guest, but
guest CPUs can migrate between host threads, so the information presented
was not consistent.  This could easily be observed with 'cpucontrol -i 0xfoo
/dev/cpuctl0'.

Slightly improve this situation by enabling the AMD topology feature flag
and presenting at least the CPUID fields used by FreeBSD itself to probe
topology on more modern AMD64 hardware (Family 15h+).  Older stuff is
probably less interesting.  I have not been able to empirically confirm it
is sufficient, but it should not regress anything either.

Reviewed by:	araujo (previous version)
Relnotes:	sure
This commit is contained in:
Conrad Meyer 2019-01-16 02:19:04 +00:00
parent 4c220feb7e
commit 15b7da10ac
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=343075
3 changed files with 116 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

151
sys/amd64/vmm/x86.c
View File

@ -136,18 +136,23 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
case CPUID_8000_0008:
cpuid_count(*eax, *ecx, regs);
if (vmm_is_amd()) {
/*
* XXX this might appear silly because AMD
* cpus don't have threads.
*
* However this matches the logical cpus as
* advertised by leaf 0x1 and will work even
* if threads is set incorrectly on an AMD host.
*/
vm_get_topology(vm, &sockets, &cores, &threads,
&maxcpus);
logical_cpus = threads * cores;
regs[2] = logical_cpus - 1;
/*
* Here, width is ApicIdCoreIdSize, present on
* at least Family 15h and newer. It
* represents the "number of bits in the
* initial apicid that indicate thread id
* within a package."
*
* Our topo_probe_amd() uses it for
* pkg_id_shift and other OSes may rely on it.
*/
width = MIN(0xF, log2(threads * cores));
if (width < 0x4)
width = 0;
logical_cpus = MIN(0xFF, threads * cores - 1);
regs[2] = (width << AMDID_COREID_SIZE_SHIFT) | logical_cpus;
}
break;
@ -155,9 +160,9 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
cpuid_count(*eax, *ecx, regs);
/*
* Hide SVM and Topology Extension features from guest.
* Hide SVM from guest.
*/
regs[2] &= ~(AMDID2_SVM | AMDID2_TOPOLOGY);
regs[2] &= ~AMDID2_SVM;
/*
* Don't advertise extended performance counter MSRs
@ -219,6 +224,68 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
regs[3] |= AMDPM_TSC_INVARIANT;
break;
case CPUID_8000_001D:
/* AMD Cache topology, like 0000_0004 for Intel. */
if (!vmm_is_amd())
goto default_leaf;
/*
* Similar to Intel, generate a ficticious cache
* topology for the guest with L3 shared by the
* package, and L1 and L2 local to a core.
*/
vm_get_topology(vm, &sockets, &cores, &threads,
&maxcpus);
switch (*ecx) {
case 0:
logical_cpus = threads;
level = 1;
func = 1; /* data cache */
break;
case 1:
logical_cpus = threads;
level = 2;
func = 3; /* unified cache */
break;
case 2:
logical_cpus = threads * cores;
level = 3;
func = 3; /* unified cache */
break;
default:
logical_cpus = 0;
level = 0;
func = 0;
break;
}
logical_cpus = MIN(0xfff, logical_cpus - 1);
regs[0] = (logical_cpus << 14) | (1 << 8) |
(level << 5) | func;
regs[1] = (func > 0) ? (CACHE_LINE_SIZE - 1) : 0;
regs[2] = 0;
regs[3] = 0;
break;
case CPUID_8000_001E:
/* AMD Family 16h+ additional identifiers */
if (!vmm_is_amd() || CPUID_TO_FAMILY(cpu_id) < 0x16)
goto default_leaf;
vm_get_topology(vm, &sockets, &cores, &threads,
&maxcpus);
regs[0] = vcpu_id;
threads = MIN(0xFF, threads - 1);
regs[1] = (threads << 8) |
(vcpu_id >> log2(threads + 1));
/*
* XXX Bhyve topology cannot yet represent >1 node per
* processor.
*/
regs[2] = 0;
regs[3] = 0;
break;
case CPUID_0000_0001:
do_cpuid(1, regs);
@ -359,7 +426,7 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
CPUID_STDEXT_AVX512F |
CPUID_STDEXT_AVX512PF |
CPUID_STDEXT_AVX512ER |
CPUID_STDEXT_AVX512CD);
CPUID_STDEXT_AVX512CD | CPUID_STDEXT_SHA);
regs[2] = 0;
regs[3] = 0;
@ -391,35 +458,42 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
case CPUID_0000_000B:
/*
* Processor topology enumeration
* Intel processor topology enumeration
*/
vm_get_topology(vm, &sockets, &cores, &threads,
&maxcpus);
if (*ecx == 0) {
logical_cpus = threads;
width = log2(logical_cpus);
level = CPUID_TYPE_SMT;
x2apic_id = vcpu_id;
}
if (vmm_is_intel()) {
vm_get_topology(vm, &sockets, &cores, &threads,
&maxcpus);
if (*ecx == 0) {
logical_cpus = threads;
width = log2(logical_cpus);
level = CPUID_TYPE_SMT;
x2apic_id = vcpu_id;
}
if (*ecx == 1) {
logical_cpus = threads * cores;
width = log2(logical_cpus);
level = CPUID_TYPE_CORE;
x2apic_id = vcpu_id;
}
if (*ecx == 1) {
logical_cpus = threads * cores;
width = log2(logical_cpus);
level = CPUID_TYPE_CORE;
x2apic_id = vcpu_id;
}
if (!cpuid_leaf_b || *ecx >= 2) {
width = 0;
logical_cpus = 0;
level = 0;
x2apic_id = 0;
}
if (!cpuid_leaf_b || *ecx >= 2) {
width = 0;
logical_cpus = 0;
level = 0;
x2apic_id = 0;
}
regs[0] = width & 0x1f;
regs[1] = logical_cpus & 0xffff;
regs[2] = (level << 8) | (*ecx & 0xff);
regs[3] = x2apic_id;
regs[0] = width & 0x1f;
regs[1] = logical_cpus & 0xffff;
regs[2] = (level << 8) | (*ecx & 0xff);
regs[3] = x2apic_id;
} else {
regs[0] = 0;
regs[1] = 0;
regs[2] = 0;
regs[3] = 0;
}
break;
case CPUID_0000_000D:
@ -481,6 +555,7 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
break;
default:
default_leaf:
/*
* The leaf value has already been clamped so
* simply pass this through, keeping count of

2
sys/amd64/vmm/x86.h
View File

@ -49,6 +49,8 @@
#define CPUID_8000_0006 (0x80000006)
#define CPUID_8000_0007 (0x80000007)
#define CPUID_8000_0008 (0x80000008)
#define CPUID_8000_001D (0x8000001D)
#define CPUID_8000_001E (0x8000001E)
/*
* CPUID instruction Fn0000_0001:

1
sys/x86/x86/mp_x86.c
View File

@ -235,6 +235,7 @@ add_deterministic_cache(int type, int level, int share_count)
* - BKDG For AMD Family 10h Processors (Publication # 31116)
* - BKDG For AMD Family 15h Models 00h-0Fh Processors (Publication # 42301)
* - BKDG For AMD Family 16h Models 00h-0Fh Processors (Publication # 48751)
* - PPR For AMD Family 17h Models 00h-0Fh Processors (Publication # 54945)
*/
static void
topo_probe_amd(void)