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tools/libxc: Rework xc_cpuid_apply_policy() to use {get,set}_cpu_policy()

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The purpose of this change is to stop using xc_cpuid_do_domctl(), and to stop
basing decisions on a local CPUID instruction.  This is not a correct or
appropriate way to construct policy information for other domains.

The overwhelming majority of this logic is redundant with the policy logic in
Xen, but has a habit of becoming stale (e.g. c/s 97e4ebdcd7 resulting in the
CPUID.7[1].eax not being offered to guests even when Xen is happy with the
content).

There are a few subtle side effects which need to remain in place.  A
successful call to xc_cpuid_apply_policy() must result in a call to
xc_set_domain_cpu_policy() because that is currently the only way the
ITSC/VMX/SVM bits become reflected in the guests CPUID view.  Future cleanup
will remove this side effect.

The topology tweaks are local to libxc.  Extend struct cpuid_policy with
enough named fields to express the logic, but keep it identical to before.
Fixing topology representation is another future area of work.

No (expected) change in behaviour.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wl@xen.org>
Release-acked-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Andrew Cooper committed 2019-09-26 13:40:18 +01:00
1 parent e5b02b085e
commit 685e922d6f
2 files changed
+219 -625
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tools/libxc/xc_cpuid_x86.c
+211 -622
View File
@@ -34,18 +34,13 @@ enum {
#include <xen/asm/x86-vendors.h>
#include <xen/lib/x86/cpuid.h>
#include <xen/lib/x86/msr.h>
#include <xen/lib/x86/cpu-policy.h>
#define bitmaskof(idx) (1u << ((idx) & 31))
#define featureword_of(idx) ((idx) >> 5)
#define clear_feature(idx, dst) ((dst) &= ~bitmaskof(idx))
#define set_feature(idx, dst) ((dst) |= bitmaskof(idx))
#define DEF_MAX_BASE 0x0000000du
#define DEF_MAX_INTELEXT 0x80000008u
#define DEF_MAX_AMDEXT 0x8000001cu
int xc_get_cpu_levelling_caps(xc_interface *xch, uint32_t *caps)
{
DECLARE_SYSCTL;
@@ -282,622 +277,6 @@ int xc_set_domain_cpu_policy(xc_interface *xch, uint32_t domid,
return ret;
}
struct cpuid_domain_info
{
unsigned int vendor; /* X86_VENDOR_* */
bool hvm;
uint64_t xfeature_mask;
/*
* Careful with featureset lengths.
*
* Code in this file requires featureset to have at least
* xc_get_cpu_featureset_size() entries. This is a libxc compiletime
* constant.
*
* The featureset length used by the hypervisor may be different. If the
* hypervisor version is longer, XEN_SYSCTL_get_cpu_featureset will fail
* with -ENOBUFS, and libxc really does need rebuilding. If the
* hypervisor version is shorter, it is safe to zero-extend.
*/
uint32_t *featureset;
unsigned int nr_features;
/* PV-only information. */
bool pv64;
/* HVM-only information. */
bool pae;
bool nestedhvm;
};
static void cpuid(const unsigned int *input, unsigned int *regs)
{
unsigned int count = (input[1] == XEN_CPUID_INPUT_UNUSED) ? 0 : input[1];
#ifdef __i386__
/* Use the stack to avoid reg constraint failures with some gcc flags */
asm (
"push %%ebx; push %%edx\n\t"
"cpuid\n\t"
"mov %%ebx,4(%4)\n\t"
"mov %%edx,12(%4)\n\t"
"pop %%edx; pop %%ebx\n\t"
: "=a" (regs[0]), "=c" (regs[2])
: "0" (input[0]), "1" (count), "S" (regs)
: "memory" );
#else
asm (
"cpuid"
: "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
: "0" (input[0]), "2" (count) );
#endif
}
static int get_cpuid_domain_info(xc_interface *xch, uint32_t domid,
struct cpuid_domain_info *info,
const uint32_t *featureset,
unsigned int nr_features)
{
struct xen_domctl domctl = {};
xc_dominfo_t di;
unsigned int in[2] = { 0, ~0U }, regs[4];
unsigned int i, host_nr_features = xc_get_cpu_featureset_size();
int rc;
cpuid(in, regs);
info->vendor = x86_cpuid_lookup_vendor(regs[1], regs[2], regs[3]);
if ( xc_domain_getinfo(xch, domid, 1, &di) != 1 ||
di.domid != domid )
return -ESRCH;
info->hvm = di.hvm;
info->featureset = calloc(host_nr_features, sizeof(*info->featureset));
if ( !info->featureset )
return -ENOMEM;
info->nr_features = host_nr_features;
if ( featureset )
{
/*
* The user supplied featureset may be shorter or longer than
* host_nr_features. Shorter is fine, and we will zero-extend.
* Longer is fine, so long as it only padded with zeros.
*/
unsigned int fslen = min(host_nr_features, nr_features);
memcpy(info->featureset, featureset,
fslen * sizeof(*info->featureset));
/* Check for truncated set bits. */
for ( i = fslen; i < nr_features; ++i )
if ( featureset[i] != 0 )
return -EOPNOTSUPP;
}
else
{
rc = xc_get_cpu_featureset(xch, (info->hvm
? XEN_SYSCTL_cpu_featureset_hvm
: XEN_SYSCTL_cpu_featureset_pv),
&host_nr_features, info->featureset);
if ( rc )
return -errno;
}
/* Get xstate information. */
domctl.cmd = XEN_DOMCTL_getvcpuextstate;
domctl.domain = domid;
rc = do_domctl(xch, &domctl);
if ( rc )
return -errno;
info->xfeature_mask = domctl.u.vcpuextstate.xfeature_mask;
if ( di.hvm )
{
uint64_t val;
rc = xc_hvm_param_get(xch, domid, HVM_PARAM_PAE_ENABLED, &val);
if ( rc )
return -errno;
info->pae = !!val;
rc = xc_hvm_param_get(xch, domid, HVM_PARAM_NESTEDHVM, &val);
if ( rc )
return -errno;
info->nestedhvm = !!val;
}
else
{
unsigned int width;
rc = xc_domain_get_guest_width(xch, domid, &width);
if ( rc )
return -errno;
info->pv64 = (width == 8);
}
return 0;
}
static void free_cpuid_domain_info(struct cpuid_domain_info *info)
{
free(info->featureset);
}
static void amd_xc_cpuid_policy(const struct cpuid_domain_info *info,
const unsigned int *input, unsigned int *regs)
{
switch ( input[0] )
{
case 0x00000002:
case 0x00000004:
regs[0] = regs[1] = regs[2] = regs[3] = 0;
break;
case 0x80000000:
if ( regs[0] > DEF_MAX_AMDEXT )
regs[0] = DEF_MAX_AMDEXT;
break;
case 0x80000008:
/*
* ECX[15:12] is ApicIdCoreSize.
* ECX[7:0] is NumberOfCores (minus one).
* Update to reflect vLAPIC_ID = vCPU_ID * 2. But make sure to avoid
* - overflow,
* - going out of sync with leaf 1 EBX[23:16],
* - incrementing ApicIdCoreSize when it's zero (which changes the
* meaning of bits 7:0).
*/
if ( (regs[2] & 0xffu) < 0x7fu )
{
if ( (regs[2] & 0xf000u) && (regs[2] & 0xf000u) != 0xf000u )
regs[2] = ((regs[2] + 0x1000u) & 0xf000u) | (regs[2] & 0xffu);
regs[2] = (regs[2] & 0xf000u) | ((regs[2] & 0x7fu) << 1) | 1u;
}
break;
case 0x8000000a: {
if ( !info->nestedhvm )
{
regs[0] = regs[1] = regs[2] = regs[3] = 0;
break;
}
#define SVM_FEATURE_NPT 0x00000001 /* Nested page table support */
#define SVM_FEATURE_LBRV 0x00000002 /* LBR virtualization support */
#define SVM_FEATURE_SVML 0x00000004 /* SVM locking MSR support */
#define SVM_FEATURE_NRIPS 0x00000008 /* Next RIP save on VMEXIT */
#define SVM_FEATURE_TSCRATEMSR 0x00000010 /* TSC ratio MSR support */
#define SVM_FEATURE_VMCBCLEAN 0x00000020 /* VMCB clean bits support */
#define SVM_FEATURE_FLUSHBYASID 0x00000040 /* TLB flush by ASID support */
#define SVM_FEATURE_DECODEASSISTS 0x00000080 /* Decode assists support */
#define SVM_FEATURE_PAUSEFILTER 0x00000400 /* Pause intercept filter */
/* Pass 1: Only passthrough SVM features which are
* available in hw and which are implemented
*/
regs[3] &= (SVM_FEATURE_NPT | SVM_FEATURE_LBRV | \
SVM_FEATURE_NRIPS | SVM_FEATURE_PAUSEFILTER | \
SVM_FEATURE_DECODEASSISTS);
/* Pass 2: Always enable SVM features which are emulated */
regs[3] |= SVM_FEATURE_VMCBCLEAN | SVM_FEATURE_TSCRATEMSR;
break;
}
}
}
static void intel_xc_cpuid_policy(const struct cpuid_domain_info *info,
const unsigned int *input, unsigned int *regs)
{
switch ( input[0] )
{
case 0x00000004:
/*
* EAX[31:26] is Maximum Cores Per Package (minus one).
* Update to reflect vLAPIC_ID = vCPU_ID * 2.
*/
regs[0] = (((regs[0] & 0x7c000000u) << 1) | 0x04000000u |
(regs[0] & 0x3ffu));
regs[3] &= 0x3ffu;
break;
case 0x80000000:
if ( regs[0] > DEF_MAX_INTELEXT )
regs[0] = DEF_MAX_INTELEXT;
break;
case 0x80000005:
regs[0] = regs[1] = regs[2] = 0;
break;
case 0x80000008:
/* Mask AMD Number of Cores information. */
regs[2] = 0;
break;
}
}
static void xc_cpuid_hvm_policy(const struct cpuid_domain_info *info,
const unsigned int *input, unsigned int *regs)
{
switch ( input[0] )
{
case 0x00000000:
if ( regs[0] > DEF_MAX_BASE )
regs[0] = DEF_MAX_BASE;
break;
case 0x00000001:
/*
* EBX[23:16] is Maximum Logical Processors Per Package.
* Update to reflect vLAPIC_ID = vCPU_ID * 2, but make sure to avoid
* overflow.
*/
if ( !(regs[1] & 0x00800000u) )
regs[1] = (regs[1] & 0x0000ffffu) | ((regs[1] & 0x007f0000u) << 1);
else
regs[1] &= 0x00ffffffu;
regs[2] = info->featureset[featureword_of(X86_FEATURE_SSE3)];
regs[3] = (info->featureset[featureword_of(X86_FEATURE_FPU)] |
bitmaskof(X86_FEATURE_HTT));
break;
case 0x00000007: /* Intel-defined CPU features */
if ( input[1] == 0 )
{
regs[1] = info->featureset[featureword_of(X86_FEATURE_FSGSBASE)];
regs[2] = info->featureset[featureword_of(X86_FEATURE_PREFETCHWT1)];
regs[3] = info->featureset[featureword_of(X86_FEATURE_AVX512_4VNNIW)];
}
else
{
regs[1] = 0;
regs[2] = 0;
regs[3] = 0;
}
regs[0] = 0;
break;
case 0x0000000d: /* Xen automatically calculates almost everything. */
if ( input[1] == 1 )
regs[0] = info->featureset[featureword_of(X86_FEATURE_XSAVEOPT)];
else
regs[0] = 0;
regs[1] = regs[2] = regs[3] = 0;
break;
case 0x80000000:
/* Passthrough to cpu vendor specific functions */
break;
case 0x80000001:
regs[2] = (info->featureset[featureword_of(X86_FEATURE_LAHF_LM)] &
~bitmaskof(X86_FEATURE_CMP_LEGACY));
regs[3] = info->featureset[featureword_of(X86_FEATURE_SYSCALL)];
break;
case 0x80000007:
/*
* Keep only TSCInvariant. This may be cleared by the hypervisor
* depending on guest TSC and migration settings.
*/
regs[0] = regs[1] = regs[2] = 0;
regs[3] &= 1u<<8;
break;
case 0x80000008:
regs[0] &= 0x0000ffffu;
regs[1] = info->featureset[featureword_of(X86_FEATURE_CLZERO)];
/* regs[2] handled in the per-vendor logic. */
regs[3] = 0;
break;
case 0x00000002: /* Intel cache info (dumped by AMD policy) */
case 0x00000004: /* Intel cache info (dumped by AMD policy) */
case 0x0000000a: /* Architectural Performance Monitor Features */
case 0x80000002: /* Processor name string */
case 0x80000003: /* ... continued */
case 0x80000004: /* ... continued */
case 0x80000005: /* AMD L1 cache/TLB info (dumped by Intel policy) */
case 0x80000006: /* AMD L2/3 cache/TLB info ; Intel L2 cache features */
case 0x8000000a: /* AMD SVM feature bits */
case 0x80000019: /* AMD 1G TLB */
case 0x8000001a: /* AMD perf hints */
case 0x8000001c: /* AMD lightweight profiling */
break;
default:
regs[0] = regs[1] = regs[2] = regs[3] = 0;
break;
}
if ( info->vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON) )
amd_xc_cpuid_policy(info, input, regs);
else
intel_xc_cpuid_policy(info, input, regs);
}
static void xc_cpuid_pv_policy(const struct cpuid_domain_info *info,
const unsigned int *input, unsigned int *regs)
{
switch ( input[0] )
{
case 0x00000000:
if ( regs[0] > DEF_MAX_BASE )
regs[0] = DEF_MAX_BASE;
break;
case 0x00000001:
{
/* Host topology exposed to PV guest. Provide host value. */
bool host_htt = regs[3] & bitmaskof(X86_FEATURE_HTT);
/*
* Don't pick host's Initial APIC ID which can change from run
* to run.
*/
regs[1] &= 0x00ffffffu;
regs[2] = info->featureset[featureword_of(X86_FEATURE_SSE3)];
regs[3] = (info->featureset[featureword_of(X86_FEATURE_FPU)] &
~bitmaskof(X86_FEATURE_HTT));
if ( host_htt )
regs[3] |= bitmaskof(X86_FEATURE_HTT);
break;
}
case 0x00000007:
if ( input[1] == 0 )
{
regs[1] = info->featureset[featureword_of(X86_FEATURE_FSGSBASE)];
regs[2] = info->featureset[featureword_of(X86_FEATURE_PREFETCHWT1)];
regs[3] = info->featureset[featureword_of(X86_FEATURE_AVX512_4VNNIW)];
}
else
{
regs[1] = 0;
regs[2] = 0;
regs[3] = 0;
}
regs[0] = 0;
break;
case 0x0000000d: /* Xen automatically calculates almost everything. */
if ( input[1] == 1 )
regs[0] = info->featureset[featureword_of(X86_FEATURE_XSAVEOPT)];
else
regs[0] = 0;
regs[1] = regs[2] = regs[3] = 0;
break;
case 0x80000000:
{
unsigned int max = (info->vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON))
? DEF_MAX_AMDEXT : DEF_MAX_INTELEXT;
if ( regs[0] > max )
regs[0] = max;
break;
}
case 0x80000001:
{
/* Host topology exposed to PV guest. Provide host CMP_LEGACY value. */
bool host_cmp_legacy = regs[2] & bitmaskof(X86_FEATURE_CMP_LEGACY);
regs[2] = (info->featureset[featureword_of(X86_FEATURE_LAHF_LM)] &
~bitmaskof(X86_FEATURE_CMP_LEGACY));
regs[3] = info->featureset[featureword_of(X86_FEATURE_SYSCALL)];
if ( host_cmp_legacy )
regs[2] |= bitmaskof(X86_FEATURE_CMP_LEGACY);
break;
}
case 0x80000008:
regs[0] &= 0x0000ffffu;
regs[1] = info->featureset[featureword_of(X86_FEATURE_CLZERO)];
regs[2] = regs[3] = 0;
break;
case 0x00000005: /* MONITOR/MWAIT */
case 0x0000000b: /* Extended Topology Enumeration */
case 0x8000000a: /* SVM revision and features */
case 0x8000001b: /* Instruction Based Sampling */
case 0x8000001c: /* Light Weight Profiling */
case 0x8000001e: /* Extended topology reporting */
regs[0] = regs[1] = regs[2] = regs[3] = 0;
break;
}
}
static void xc_cpuid_policy(const struct cpuid_domain_info *info,
const unsigned int *input, unsigned int *regs)
{
/*
* For hypervisor leaves (0x4000XXXX) only 0x4000xx00.EAX[7:0] bits (max
* number of leaves) can be set by user. Hypervisor will enforce this so
* all other bits are don't-care and we can set them to zero.
*/
if ( (input[0] & 0xffff0000) == 0x40000000 )
{
regs[0] = regs[1] = regs[2] = regs[3] = 0;
return;
}
if ( info->hvm )
xc_cpuid_hvm_policy(info, input, regs);
else
xc_cpuid_pv_policy(info, input, regs);
}
static int xc_cpuid_do_domctl(
xc_interface *xch, uint32_t domid,
const unsigned int *input, const unsigned int *regs)
{
DECLARE_DOMCTL;
memset(&domctl, 0, sizeof (domctl));
domctl.domain = domid;
domctl.cmd = XEN_DOMCTL_set_cpuid;
domctl.u.cpuid.input[0] = input[0];
domctl.u.cpuid.input[1] = input[1];
domctl.u.cpuid.eax = regs[0];
domctl.u.cpuid.ebx = regs[1];
domctl.u.cpuid.ecx = regs[2];
domctl.u.cpuid.edx = regs[3];
return do_domctl(xch, &domctl);
}
static void sanitise_featureset(struct cpuid_domain_info *info)
{
const uint32_t fs_size = xc_get_cpu_featureset_size();
uint32_t disabled_features[fs_size];
static const uint32_t deep_features[] = INIT_DEEP_FEATURES;
unsigned int i, b;
if ( info->hvm )
{
/* HVM or PVH Guest */
if ( !info->pae )
clear_bit(X86_FEATURE_PAE, info->featureset);
if ( !info->nestedhvm )
{
clear_bit(X86_FEATURE_SVM, info->featureset);
clear_bit(X86_FEATURE_VMX, info->featureset);
}
}
else
{
/* PV Guest */
if ( !info->pv64 )
{
clear_bit(X86_FEATURE_LM, info->featureset);
if ( !(info->vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON)) )
clear_bit(X86_FEATURE_SYSCALL, info->featureset);
}
clear_bit(X86_FEATURE_PSE, info->featureset);
clear_bit(X86_FEATURE_PSE36, info->featureset);
clear_bit(X86_FEATURE_PGE, info->featureset);
clear_bit(X86_FEATURE_PAGE1GB, info->featureset);
}
if ( info->xfeature_mask == 0 )
clear_bit(X86_FEATURE_XSAVE, info->featureset);
/* Disable deep dependencies of disabled features. */
for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
disabled_features[i] = ~info->featureset[i] & deep_features[i];
for ( b = 0; b < sizeof(disabled_features) * CHAR_BIT; ++b )
{
const uint32_t *dfs;
if ( !test_bit(b, disabled_features) ||
!(dfs = x86_cpuid_lookup_deep_deps(b)) )
continue;
for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
{
info->featureset[i] &= ~dfs[i];
disabled_features[i] &= ~dfs[i];
}
}
}
int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid,
const uint32_t *featureset, unsigned int nr_features)
{
struct cpuid_domain_info info = {};
unsigned int input[2] = { 0, 0 }, regs[4];
unsigned int base_max, ext_max;
int rc;
rc = get_cpuid_domain_info(xch, domid, &info, featureset, nr_features);
if ( rc )
goto out;
cpuid(input, regs);
base_max = (regs[0] <= DEF_MAX_BASE) ? regs[0] : DEF_MAX_BASE;
input[0] = 0x80000000;
cpuid(input, regs);
if ( info.vendor == X86_VENDOR_AMD || info.vendor == X86_VENDOR_HYGON )
ext_max = (regs[0] <= DEF_MAX_AMDEXT) ? regs[0] : DEF_MAX_AMDEXT;
else
ext_max = (regs[0] <= DEF_MAX_INTELEXT) ? regs[0] : DEF_MAX_INTELEXT;
sanitise_featureset(&info);
input[0] = 0;
input[1] = XEN_CPUID_INPUT_UNUSED;
for ( ; ; )
{
cpuid(input, regs);
xc_cpuid_policy(&info, input, regs);
if ( regs[0] || regs[1] || regs[2] || regs[3] )
{
rc = xc_cpuid_do_domctl(xch, domid, input, regs);
if ( rc )
goto out;
}
/* Intel cache descriptor leaves. */
if ( input[0] == 4 )
{
input[1]++;
/* More to do? Then loop keeping %%eax==0x00000004. */
if ( (regs[0] & 0x1f) != 0 )
continue;
}
/* Extended Topology leaves. */
else if ( input[0] == 0xb )
{
uint8_t level_type = regs[2] >> 8;
input[1]++;
if ( level_type >= 1 && level_type <= 2 )
continue;
}
input[0]++;
if ( !(input[0] & 0x80000000u) && (input[0] > base_max ) )
input[0] = 0x80000000u;
input[1] = XEN_CPUID_INPUT_UNUSED;
if ( (input[0] == 4) || (input[0] == 7) || (input[0] == 0xb) )
input[1] = 0;
else if ( input[0] == 0xd )
input[1] = 1; /* Xen automatically calculates almost everything. */
if ( (input[0] & 0x80000000u) && (input[0] > ext_max) )
break;
}
out:
free_cpuid_domain_info(&info);
return rc;
}
/*
* Configure a single input with the informatiom from config.
*
@@ -1074,3 +453,213 @@ int xc_cpuid_set(
return rc;
}
int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid,
const uint32_t *featureset, unsigned int nr_features)
{
int rc;
xc_dominfo_t di;
unsigned int i, nr_leaves, nr_msrs;
xen_cpuid_leaf_t *leaves = NULL;
struct cpuid_policy *p = NULL;
uint32_t err_leaf = -1, err_subleaf = -1, err_msr = -1;
if ( xc_domain_getinfo(xch, domid, 1, &di) != 1 ||
di.domid != domid )
{
ERROR("Failed to obtain d%d info", domid);
rc = -ESRCH;
goto out;
}
rc = xc_get_cpu_policy_size(xch, &nr_leaves, &nr_msrs);
if ( rc )
{
PERROR("Failed to obtain policy info size");
rc = -errno;
goto out;
}
rc = -ENOMEM;
if ( (leaves = calloc(nr_leaves, sizeof(*leaves))) == NULL ||
(p = calloc(1, sizeof(*p))) == NULL )
goto out;
/* Get the domain's default policy. */
nr_msrs = 0;
rc = xc_get_system_cpu_policy(xch, di.hvm ? XEN_SYSCTL_cpu_policy_hvm_default
: XEN_SYSCTL_cpu_policy_pv_default,
&nr_leaves, leaves, &nr_msrs, NULL);
if ( rc )
{
PERROR("Failed to obtain %s default policy", di.hvm ? "hvm" : "pv");
rc = -errno;
goto out;
}
rc = x86_cpuid_copy_from_buffer(p, leaves, nr_leaves,
&err_leaf, &err_subleaf);
if ( rc )
{
ERROR("Failed to deserialise CPUID (err leaf %#x, subleaf %#x) (%d = %s)",
err_leaf, err_subleaf, -rc, strerror(-rc));
goto out;
}
if ( featureset )
{
uint32_t disabled_features[FEATURESET_NR_ENTRIES],
feat[FEATURESET_NR_ENTRIES] = {};
static const uint32_t deep_features[] = INIT_DEEP_FEATURES;
unsigned int i, b;
/*
* The user supplied featureset may be shorter or longer than
* FEATURESET_NR_ENTRIES. Shorter is fine, and we will zero-extend.
* Longer is fine, so long as it only padded with zeros.
*/
unsigned int user_len = min(FEATURESET_NR_ENTRIES + 0u, nr_features);
/* Check for truncated set bits. */
rc = -EOPNOTSUPP;
for ( i = user_len; i < nr_features; ++i )
if ( featureset[i] != 0 )
goto out;
memcpy(feat, featureset, sizeof(*featureset) * user_len);
/* Disable deep dependencies of disabled features. */
for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
disabled_features[i] = ~feat[i] & deep_features[i];
for ( b = 0; b < sizeof(disabled_features) * CHAR_BIT; ++b )
{
const uint32_t *dfs;
if ( !test_bit(b, disabled_features) ||
!(dfs = x86_cpuid_lookup_deep_deps(b)) )
continue;
for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
{
feat[i] &= ~dfs[i];
disabled_features[i] &= ~dfs[i];
}
}
cpuid_featureset_to_policy(feat, p);
}
if ( !di.hvm )
{
uint32_t host_featureset[FEATURESET_NR_ENTRIES] = {};
uint32_t len = ARRAY_SIZE(host_featureset);
rc = xc_get_cpu_featureset(xch, XEN_SYSCTL_cpu_featureset_host,
&len, host_featureset);
if ( rc )
{
/* Tolerate "buffer too small", as we've got the bits we need. */
if ( errno == ENOBUFS )
rc = 0;
else
{
PERROR("Failed to obtain host featureset");
rc = -errno;
goto out;
}
}
/*
* On hardware without CPUID Faulting, PV guests see real topology.
* As a consequence, they also need to see the host htt/cmp fields.
*/
p->basic.htt = test_bit(X86_FEATURE_HTT, host_featureset);
p->extd.cmp_legacy = test_bit(X86_FEATURE_CMP_LEGACY, host_featureset);
}
else
{
/*
* Topology for HVM guests is entirely controlled by Xen. For now, we
* hardcode APIC_ID = vcpu_id * 2 to give the illusion of no SMT.
*/
p->basic.htt = true;
p->extd.cmp_legacy = false;
/*
* Leaf 1 EBX[23:16] is Maximum Logical Processors Per Package.
* Update to reflect vLAPIC_ID = vCPU_ID * 2, but make sure to avoid
* overflow.
*/
if ( !(p->basic.lppp & 0x80) )
p->basic.lppp *= 2;
switch ( p->x86_vendor )
{
case X86_VENDOR_INTEL:
for ( i = 0; (p->cache.subleaf[i].type &&
i < ARRAY_SIZE(p->cache.raw)); ++i )
{
p->cache.subleaf[i].cores_per_package =
(p->cache.subleaf[i].cores_per_package << 1) | 1;
p->cache.subleaf[i].threads_per_cache = 0;
}
break;
case X86_VENDOR_AMD:
case X86_VENDOR_HYGON:
/*
* Leaf 0x80000008 ECX[15:12] is ApicIdCoreSize.
* Leaf 0x80000008 ECX[7:0] is NumberOfCores (minus one).
* Update to reflect vLAPIC_ID = vCPU_ID * 2. But avoid
* - overflow,
* - going out of sync with leaf 1 EBX[23:16],
* - incrementing ApicIdCoreSize when it's zero (which changes the
* meaning of bits 7:0).
*/
if ( p->extd.nc < 0x7f )
{
if ( p->extd.apic_id_size != 0 && p->extd.apic_id_size != 0xf )
p->extd.apic_id_size++;
p->extd.nc = (p->extd.nc << 1) | 1;
}
break;
}
/*
* These settings are necessary to cause earlier HVM_PARAM_NESTEDHVM /
* XEN_DOMCTL_disable_migrate settings to be reflected correctly in
* CPUID. Xen will discard these bits if configuration hasn't been
* set for the domain.
*/
p->extd.itsc = true;
p->basic.vmx = true;
p->extd.svm = true;
}
rc = x86_cpuid_copy_to_buffer(p, leaves, &nr_leaves);
if ( rc )
{
ERROR("Failed to serialise CPUID (%d = %s)", -rc, strerror(-rc));
goto out;
}
rc = xc_set_domain_cpu_policy(xch, domid, nr_leaves, leaves, 0, NULL,
&err_leaf, &err_subleaf, &err_msr);
if ( rc )
{
PERROR("Failed to set d%d's policy (err leaf %#x, subleaf %#x, msr %#x)",
domid, err_leaf, err_subleaf, err_msr);
rc = -errno;
goto out;
}
rc = 0;
out:
free(p);
free(leaves);
return rc;
}
xen/include/xen/lib/x86/cpuid.h
+8 -3
View File
@@ -154,8 +154,12 @@ struct cpuid_policy
union {
struct cpuid_leaf raw[CPUID_GUEST_NR_CACHE];
struct cpuid_cache_leaf {
uint32_t type:5,
:27, :32, :32, :32;
uint32_t /* a */ type:5, level:3;
bool self_init:1, fully_assoc:1;
uint32_t :4, threads_per_cache:12, cores_per_package:6;
uint32_t /* b */ line_size:12, partitions:10, ways:10;
uint32_t /* c */ sets;
bool /* d */ wbinvd:1, inclusive:1, complex:1;
} subleaf[CPUID_GUEST_NR_CACHE];
} cache;
@@ -259,7 +263,8 @@ struct cpuid_policy
uint32_t e8b;
struct { DECL_BITFIELD(e8b); };
};
uint32_t /* c */:32, /* d */:32;
uint32_t nc:8, :4, apic_id_size:4, :16;
uint32_t /* d */:32;
};
} extd;
Reference in new issue
xen-project/xen
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