* [Qemu-devel] [PATCH for-2.9 v3 1/3] i386: host_vendor_fms() helper function
2017-03-09 18:12 [Qemu-devel] [PATCH for-2.9 v3 0/3] Use non-blacklisted family/model/stepping for Haswell CPU model Eduardo Habkost
@ 2017-03-09 18:12 ` Eduardo Habkost
2017-03-09 18:12 ` [Qemu-devel] [PATCH for-2.9 v3 2/3] i386/kvm: Blacklist TSX on known broken hosts Eduardo Habkost
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Eduardo Habkost @ 2017-03-09 18:12 UTC (permalink / raw)
To: qemu-devel; +Cc: libvir-list
Helper function for code that needs to check the host CPU
vendor/family/model/stepping values.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
Changes v2 -> v3:
* Don't touch max_x86_cpu_initfn() to reduce risk post
hard freeze
Changes v1 -> v2:
* Coding style fix (split long lines)
---
target/i386/cpu.h | 1 +
target/i386/cpu.c | 19 +++++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index ac2ad6d443..385dcc8fea 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1436,6 +1436,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
void cpu_clear_apic_feature(CPUX86State *env);
void host_cpuid(uint32_t function, uint32_t count,
uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx);
+void host_vendor_fms(char *vendor, int *family, int *model, int *stepping);
/* helper.c */
int x86_cpu_handle_mmu_fault(CPUState *cpu, vaddr addr,
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index fba92125ab..30ba1bd06b 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -688,6 +688,25 @@ void host_cpuid(uint32_t function, uint32_t count,
*edx = vec[3];
}
+void host_vendor_fms(char *vendor, int *family, int *model, int *stepping)
+{
+ uint32_t eax, ebx, ecx, edx;
+
+ host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
+ x86_cpu_vendor_words2str(vendor, ebx, edx, ecx);
+
+ host_cpuid(0x1, 0, &eax, &ebx, &ecx, &edx);
+ if (family) {
+ *family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
+ }
+ if (model) {
+ *model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
+ }
+ if (stepping) {
+ *stepping = eax & 0x0F;
+ }
+}
+
/* CPU class name definitions: */
#define X86_CPU_TYPE_SUFFIX "-" TYPE_X86_CPU
--
2.11.0.259.g40922b1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Qemu-devel] [PATCH for-2.9 v3 2/3] i386/kvm: Blacklist TSX on known broken hosts
2017-03-09 18:12 [Qemu-devel] [PATCH for-2.9 v3 0/3] Use non-blacklisted family/model/stepping for Haswell CPU model Eduardo Habkost
2017-03-09 18:12 ` [Qemu-devel] [PATCH for-2.9 v3 1/3] i386: host_vendor_fms() helper function Eduardo Habkost
@ 2017-03-09 18:12 ` Eduardo Habkost
2017-03-09 18:12 ` [Qemu-devel] [PATCH for-2.9 v3 3/3] i386: Change stepping of Haswell to non-blacklisted value Eduardo Habkost
2017-03-10 18:04 ` [Qemu-devel] [PATCH for-2.9 v3 0/3] Use non-blacklisted family/model/stepping for Haswell CPU model Eduardo Habkost
3 siblings, 0 replies; 5+ messages in thread
From: Eduardo Habkost @ 2017-03-09 18:12 UTC (permalink / raw)
To: qemu-devel; +Cc: libvir-list
Some Intel CPUs are known to have a broken TSX implementation. A
microcode update from Intel disabled TSX on those CPUs, but
GET_SUPPORTED_CPUID might be reporting it as supported if the
hosts were not updated yet.
Manually fixup the GET_SUPPORTED_CPUID data to ensure we will
never enable TSX when running on those hosts.
Reference:
* glibc commit 2702856bf45c82cf8e69f2064f5aa15c0ceb6359:
https://sourceware.org/git/?p=glibc.git;a=commit;h=2702856bf45c82cf8e69f2064f5aa15c0ceb6359
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
target/i386/kvm.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 887a81268f..472399fb2c 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -266,6 +266,19 @@ static int get_para_features(KVMState *s)
return features;
}
+static bool host_tsx_blacklisted(void)
+{
+ int family, model, stepping;\
+ char vendor[CPUID_VENDOR_SZ + 1];
+
+ host_vendor_fms(vendor, &family, &model, &stepping);
+
+ /* Check if we are running on a Haswell host known to have broken TSX */
+ return !strcmp(vendor, CPUID_VENDOR_INTEL) &&
+ (family == 6) &&
+ ((model == 63 && stepping < 4) ||
+ model == 60 || model == 69 || model == 70);
+}
/* Returns the value for a specific register on the cpuid entry
*/
@@ -349,6 +362,10 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
}
} else if (function == 6 && reg == R_EAX) {
ret |= CPUID_6_EAX_ARAT; /* safe to allow because of emulated APIC */
+ } else if (function == 7 && index == 0 && reg == R_EBX) {
+ if (host_tsx_blacklisted()) {
+ ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE);
+ }
} else if (function == 0x80000001 && reg == R_EDX) {
/* On Intel, kvm returns cpuid according to the Intel spec,
* so add missing bits according to the AMD spec:
--
2.11.0.259.g40922b1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Qemu-devel] [PATCH for-2.9 v3 3/3] i386: Change stepping of Haswell to non-blacklisted value
2017-03-09 18:12 [Qemu-devel] [PATCH for-2.9 v3 0/3] Use non-blacklisted family/model/stepping for Haswell CPU model Eduardo Habkost
2017-03-09 18:12 ` [Qemu-devel] [PATCH for-2.9 v3 1/3] i386: host_vendor_fms() helper function Eduardo Habkost
2017-03-09 18:12 ` [Qemu-devel] [PATCH for-2.9 v3 2/3] i386/kvm: Blacklist TSX on known broken hosts Eduardo Habkost
@ 2017-03-09 18:12 ` Eduardo Habkost
2017-03-10 18:04 ` [Qemu-devel] [PATCH for-2.9 v3 0/3] Use non-blacklisted family/model/stepping for Haswell CPU model Eduardo Habkost
3 siblings, 0 replies; 5+ messages in thread
From: Eduardo Habkost @ 2017-03-09 18:12 UTC (permalink / raw)
To: qemu-devel; +Cc: libvir-list
glibc blacklists TSX on Haswell CPUs with model==60 and
stepping < 4. To make the Haswell CPU model more useful, make
those guests actually use TSX by changing CPU stepping to 4.
References:
* glibc commit 2702856bf45c82cf8e69f2064f5aa15c0ceb6359
https://sourceware.org/git/?p=glibc.git;a=commit;h=2702856bf45c82cf8e69f2064f5aa15c0ceb6359
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
include/hw/i386/pc.h | 5 +++++
target/i386/cpu.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index ab303c7fee..f278b3ae89 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -389,6 +389,11 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
.driver = TYPE_X86_CPU,\
.property = "vmware-cpuid-freq",\
.value = "off",\
+ },\
+ {\
+ .driver = "Haswell-" TYPE_X86_CPU,\
+ .property = "stepping",\
+ .value = "1",\
},
#define PC_COMPAT_2_7 \
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 30ba1bd06b..7aa762245a 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1196,7 +1196,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
.vendor = CPUID_VENDOR_INTEL,
.family = 6,
.model = 60,
- .stepping = 1,
+ .stepping = 4,
.features[FEAT_1_EDX] =
CPUID_VME | CPUID_SSE2 | CPUID_SSE | CPUID_FXSR | CPUID_MMX |
CPUID_CLFLUSH | CPUID_PSE36 | CPUID_PAT | CPUID_CMOV | CPUID_MCA |
--
2.11.0.259.g40922b1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH for-2.9 v3 0/3] Use non-blacklisted family/model/stepping for Haswell CPU model
2017-03-09 18:12 [Qemu-devel] [PATCH for-2.9 v3 0/3] Use non-blacklisted family/model/stepping for Haswell CPU model Eduardo Habkost
` (2 preceding siblings ...)
2017-03-09 18:12 ` [Qemu-devel] [PATCH for-2.9 v3 3/3] i386: Change stepping of Haswell to non-blacklisted value Eduardo Habkost
@ 2017-03-10 18:04 ` Eduardo Habkost
3 siblings, 0 replies; 5+ messages in thread
From: Eduardo Habkost @ 2017-03-10 18:04 UTC (permalink / raw)
To: qemu-devel
Cc: fweimer, libvir-list, dgilbert, carlos, pbonzini, jdenemar,
triegel
On Thu, Mar 09, 2017 at 03:12:09PM -0300, Eduardo Habkost wrote:
> I plan to merge this bug fix into 2.9.
I'm queueing this on my x86-next branch.
>
> Changes v2 -> v3:
> * Rebase to latest master
> * Don't touch max_x86_cpu_initfn() to reduce risk post
> hard freeze
>
> Changes v1 -> v2:
> * Coding style fixes
> * Make series simpler:
> * Don't use trick: char vendor[static (CPUID_VENDOR_SZ + 1)]
> because it confuses checkpatch.pl
> * Removed patch "Add explicit array size to x86_cpu_vendor_words2str()"
> * Rebased on top of my x86-next branch:
> https://github.com/ehabkost/qemu x86-next
>
> Git branch for testing:
> https://github.com/ehabkost/qemu-hacks work/x86-rtm-blacklist
>
> Diff from v1:
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index cd94726e43..647435a1d9 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1431,7 +1431,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
> void cpu_clear_apic_feature(CPUX86State *env);
> void host_cpuid(uint32_t function, uint32_t count,
> uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx);
> -void host_vendor_fms(char vendor[static (CPUID_VENDOR_SZ + 1)], int *family, int *model, int *stepping);
> +void host_vendor_fms(char *vendor, int *family, int *model, int *stepping);
>
> /* helper.c */
> int x86_cpu_handle_mmu_fault(CPUState *cpu, vaddr addr,
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 25c6c5e115..eab1ad7935 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -682,7 +682,7 @@ void host_cpuid(uint32_t function, uint32_t count,
> *edx = vec[3];
> }
>
> -void host_vendor_fms(char vendor[static (CPUID_VENDOR_SZ + 1)], int *family, int *model, int *stepping)
> +void host_vendor_fms(char *vendor, int *family, int *model, int *stepping)
> {
> uint32_t eax, ebx, ecx, edx;
>
> @@ -1570,7 +1570,8 @@ static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
> xcc->kvm_required = true;
> xcc->ordering = 9;
>
> - host_vendor_fms(host_cpudef.vendor, &host_cpudef.family, &host_cpudef.model, &host_cpudef.stepping);
> + host_vendor_fms(host_cpudef.vendor, &host_cpudef.family,
> + &host_cpudef.model, &host_cpudef.stepping);
>
> cpu_x86_fill_model_id(host_cpudef.model_id);
>
> ---
>
> A recent glibc commit[1] added a blacklist to ensure it won't use
> TSX on hosts that are known to have a broken TSX implementation.
>
> Our existing Haswell CPU model has a blacklisted
> family/model/stepping combination, so it has to be updated to
> make sure guests will really use TSX. This is done by patch 5/5.
>
> However, to do this safely we need to ensure the host CPU is not
> a blacklisted one, so we won't mislead guests by exposing
> known-to-be-good FMS values on a known-to-be-broken host. This is
> done by patch 3/5.
>
> [1] https://sourceware.org/git/?p=glibc.git;a=commit;h=2702856bf45c82cf8e69f2064f5aa15c0ceb6359
>
> ---
> Cc: dgilbert@redhat.com
> Cc: fweimer@redhat.com
> Cc: carlos@redhat.com
> Cc: triegel@redhat.com
> Cc: berrange@redhat.com
> Cc: jdenemar@redhat.com
> Cc: pbonzini@redhat.com
>
> Eduardo Habkost (3):
> i386: host_vendor_fms() helper function
> i386/kvm: Blacklist TSX on known broken hosts
> i386: Change stepping of Haswell to non-blacklisted value
>
> include/hw/i386/pc.h | 5 +++++
> target/i386/cpu.h | 1 +
> target/i386/cpu.c | 21 ++++++++++++++++++++-
> target/i386/kvm.c | 17 +++++++++++++++++
> 4 files changed, 43 insertions(+), 1 deletion(-)
>
> --
> 2.11.0.259.g40922b1
>
>
--
Eduardo
^ permalink raw reply [flat|nested] 5+ messages in thread