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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 3/6] x86/cpuid: Move all xstate leaf handling into guest_cpuid()
The xstate union now contains sanitised values, so it can be handled fully in
the non-legacy path.
c/s 1c0bc709d "x86/cpuid: Perform max_leaf calculations in guest_cpuid()"
accidentally introduced a boundary error for the subleaf check, although it
was masked by the correct logic in the legacy path.
Two dynamic adjustments need making, but a TODO and BUILD_BUG_ON() are left to
cover a latent bug which will present itself when Xen starts supporting XSS
states for guests.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
---
xen/arch/x86/cpuid.c | 179 +++++++---------------------------------
xen/arch/x86/domctl.c | 4 +-
xen/include/asm-x86/processor.h | 10 +++
3 files changed, 45 insertions(+), 148 deletions(-)
diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index 303568d..9f16502 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -484,8 +484,6 @@ static void pv_cpuid(uint32_t leaf, uint32_t subleaf,
struct cpuid_leaf *res)
switch ( leaf )
{
- uint32_t tmp;
-
case 0x00000001:
res->c = p->basic._1c;
res->d = p->basic._1d;
@@ -637,57 +635,6 @@ static void pv_cpuid(uint32_t leaf, uint32_t subleaf,
struct cpuid_leaf *res)
res->a = (res->a & ~0xff) | 3;
break;
- case XSTATE_CPUID:
- if ( !p->basic.xsave || subleaf >= 63 )
- goto unsupported;
- switch ( subleaf )
- {
- case 0:
- {
- uint64_t xfeature_mask = XSTATE_FP_SSE;
- uint32_t xstate_size = XSTATE_AREA_MIN_SIZE;
-
- if ( p->basic.avx )
- {
- xfeature_mask |= XSTATE_YMM;
- xstate_size = (xstate_offsets[_XSTATE_YMM] +
- xstate_sizes[_XSTATE_YMM]);
- }
-
- if ( p->feat.avx512f )
- {
- xfeature_mask |= XSTATE_OPMASK | XSTATE_ZMM | XSTATE_HI_ZMM;
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_OPMASK] +
- xstate_sizes[_XSTATE_OPMASK]);
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_ZMM] +
- xstate_sizes[_XSTATE_ZMM]);
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_HI_ZMM] +
- xstate_sizes[_XSTATE_HI_ZMM]);
- }
-
- res->a = xfeature_mask;
- res->d = xfeature_mask >> 32;
- res->c = xstate_size;
-
- /*
- * Always read CPUID.0xD[ECX=0].EBX from hardware, rather than
- * domain policy. It varies with enabled xstate, and the correct
- * xcr0 is in context.
- */
- cpuid_count(leaf, subleaf, &tmp, &res->b, &tmp, &tmp);
- break;
- }
-
- case 1:
- res->a = p->xstate.Da1;
- res->b = res->c = res->d = 0;
- break;
- }
- break;
-
case 0x80000001:
res->c = p->extd.e1c;
res->d = p->extd.e1d;
@@ -730,6 +677,7 @@ static void pv_cpuid(uint32_t leaf, uint32_t subleaf,
struct cpuid_leaf *res)
break;
case 0x7:
+ case XSTATE_CPUID:
ASSERT_UNREACHABLE();
/* Now handled in guest_cpuid(). */
}
@@ -797,98 +745,6 @@ static void hvm_cpuid(uint32_t leaf, uint32_t subleaf,
struct cpuid_leaf *res)
res->d = v->vcpu_id * 2;
break;
- case XSTATE_CPUID:
- if ( !p->basic.xsave || subleaf >= 63 )
- {
- *res = EMPTY_LEAF;
- break;
- }
- switch ( subleaf )
- {
- case 0:
- {
- uint64_t xfeature_mask = XSTATE_FP_SSE;
- uint32_t xstate_size = XSTATE_AREA_MIN_SIZE;
-
- if ( p->basic.avx )
- {
- xfeature_mask |= XSTATE_YMM;
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_YMM] +
- xstate_sizes[_XSTATE_YMM]);
- }
-
- if ( p->feat.mpx )
- {
- xfeature_mask |= XSTATE_BNDREGS | XSTATE_BNDCSR;
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_BNDCSR] +
- xstate_sizes[_XSTATE_BNDCSR]);
- }
-
- if ( p->feat.avx512f )
- {
- xfeature_mask |= XSTATE_OPMASK | XSTATE_ZMM | XSTATE_HI_ZMM;
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_OPMASK] +
- xstate_sizes[_XSTATE_OPMASK]);
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_ZMM] +
- xstate_sizes[_XSTATE_ZMM]);
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_HI_ZMM] +
- xstate_sizes[_XSTATE_HI_ZMM]);
- }
-
- if ( p->feat.pku )
- {
- xfeature_mask |= XSTATE_PKRU;
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_PKRU] +
- xstate_sizes[_XSTATE_PKRU]);
- }
-
- if ( p->extd.lwp )
- {
- xfeature_mask |= XSTATE_LWP;
- xstate_size = max(xstate_size,
- xstate_offsets[_XSTATE_LWP] +
- xstate_sizes[_XSTATE_LWP]);
- }
-
- res->a = xfeature_mask;
- res->d = xfeature_mask >> 32;
- res->c = xstate_size;
-
- /*
- * Always read CPUID[0xD,0].EBX from hardware, rather than domain
- * policy. It varies with enabled xstate, and the correct xcr0 is
- * in context.
- */
- cpuid_count(leaf, subleaf, &tmp, &res->b, &tmp, &tmp);
- break;
- }
-
- case 1:
- res->a = p->xstate.Da1;
-
- if ( p->xstate.xsaves )
- {
- /*
- * Always read CPUID[0xD,1].EBX from hardware, rather than
- * domain policy. It varies with enabled xstate, and the
- * correct xcr0/xss are in context.
- */
- cpuid_count(leaf, subleaf, &tmp, &res->b, &tmp, &tmp);
- }
- else
- res->b = 0;
-
- res->c = res->d = 0;
- break;
- }
- break;
-
case 0x0000000a: /* Architectural Performance Monitor Features (Intel) */
if ( boot_cpu_data.x86_vendor != X86_VENDOR_INTEL || !vpmu_enabled(v) )
{
@@ -970,6 +826,7 @@ static void hvm_cpuid(uint32_t leaf, uint32_t subleaf,
struct cpuid_leaf *res)
break;
case 0x7:
+ case XSTATE_CPUID:
ASSERT_UNREACHABLE();
/* Now handled in guest_cpuid(). */
}
@@ -1007,10 +864,13 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
break;
case XSTATE_CPUID:
- if ( subleaf > ARRAY_SIZE(p->xstate.raw) )
+ if ( !p->basic.xsave || subleaf >= ARRAY_SIZE(p->xstate.raw) )
return;
- /* Fallthrough. */
+ BUG_ON(subleaf >= ARRAY_SIZE(p->xstate.raw));
+ *res = p->xstate.raw[subleaf];
+ break;
+
default:
goto legacy;
}
@@ -1067,6 +927,31 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
break;
}
break;
+
+ case XSTATE_CPUID:
+ switch ( subleaf )
+ {
+ case 1:
+ if ( p->xstate.xsaves )
+ {
+ /*
+ * TODO: Figure out what to do for XSS state. VT-x manages
+ * host vs guest MSR_XSS automatically, so as soon as we start
+ * supporting any XSS states, the wrong XSS will be in
+ * context.
+ */
+ BUILD_BUG_ON(XSTATE_XSAVES_ONLY != 0);
+
+ /*
+ * Read CPUID[0xD,0/1].EBX from hardware. They vary with
+ * enabled XSTATE, and appropraite XCR0|XSS are in context.
+ */
+ case 0:
+ res->b = cpuid_count_ebx(leaf, subleaf);
+ }
+ break;
+ }
+ break;
}
/* Done. */
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 772c5d2..8e8437d 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -105,8 +105,10 @@ static int update_domain_cpuid_info(struct domain *d,
if ( ctl->input[0] == 7 &&
ctl->input[1] >= ARRAY_SIZE(p->feat.raw) )
return 0;
+
+ BUILD_BUG_ON(ARRAY_SIZE(p->xstate.raw) < 2);
if ( ctl->input[0] == XSTATE_CPUID &&
- ctl->input[1] >= ARRAY_SIZE(p->xstate.raw) )
+ ctl->input[1] != 1 ) /* Everything else automatically calculated.
*/
return 0;
break;
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index b130f47..54d0a17 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -319,6 +319,16 @@ static always_inline unsigned int cpuid_edx(unsigned int
op)
return edx;
}
+static always_inline unsigned int cpuid_count_ebx(
+ unsigned int leaf, unsigned int subleaf)
+{
+ unsigned int ebx, tmp;
+
+ cpuid_count(leaf, subleaf, &tmp, &ebx, &tmp, &tmp);
+
+ return ebx;
+}
+
static inline unsigned long read_cr0(void)
{
unsigned long cr0;
--
2.1.4
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