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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] Temporarily revert "amd/msr: allow passthrough of VIRT_SPEC_CTRL for HVM guests"
commit bc7f400b968fa3f660c26bdc53f5efa394bbfcd1
Author: George Dunlap <george.dunlap@xxxxxxxxxx>
AuthorDate: Fri Aug 19 20:17:30 2022 +0100
Commit: George Dunlap <george.dunlap@xxxxxxxxxx>
CommitDate: Fri Aug 19 20:21:57 2022 +0100
Temporarily revert "amd/msr: allow passthrough of VIRT_SPEC_CTRL for HVM
guests"
A person tagged in commit a2eeaa6906101fbf322766f37f8f061dd36fe58d
claims the tag is in accurate; revert this commit so that we can
re-commit it again with the tag corrected.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
---
xen/arch/x86/cpuid.c | 14 --------------
xen/arch/x86/hvm/svm/entry.S | 8 --------
xen/arch/x86/hvm/svm/svm.c | 35 ----------------------------------
xen/arch/x86/include/asm/cpufeatures.h | 2 +-
xen/arch/x86/include/asm/msr.h | 10 ----------
xen/arch/x86/msr.c | 16 ++++------------
xen/arch/x86/spec_ctrl.c | 9 +--------
7 files changed, 6 insertions(+), 88 deletions(-)
diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index a4a366ad84..979dcf8164 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -541,13 +541,6 @@ static void __init calculate_hvm_max_policy(void)
raw_cpuid_policy.basic.sep )
__set_bit(X86_FEATURE_SEP, hvm_featureset);
- /*
- * VIRT_SSBD is exposed in the default policy as a result of
- * VIRT_SC_MSR_HVM being set, it also needs exposing in the max policy.
- */
- if ( boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM) )
- __set_bit(X86_FEATURE_VIRT_SSBD, hvm_featureset);
-
/*
* If Xen isn't virtualising MSR_SPEC_CTRL for HVM guests (functional
* availability, or admin choice), hide the feature.
@@ -604,13 +597,6 @@ static void __init calculate_hvm_def_policy(void)
guest_common_feature_adjustments(hvm_featureset);
guest_common_default_feature_adjustments(hvm_featureset);
- /*
- * Only expose VIRT_SSBD if AMD_SSBD is not available, and thus
- * VIRT_SC_MSR_HVM is set.
- */
- if ( boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM) )
- __set_bit(X86_FEATURE_VIRT_SSBD, hvm_featureset);
-
sanitise_featureset(hvm_featureset);
cpuid_featureset_to_policy(hvm_featureset, p);
recalculate_xstate(p);
diff --git a/xen/arch/x86/hvm/svm/entry.S b/xen/arch/x86/hvm/svm/entry.S
index a26589aa9a..a60d759f71 100644
--- a/xen/arch/x86/hvm/svm/entry.S
+++ b/xen/arch/x86/hvm/svm/entry.S
@@ -19,8 +19,6 @@
.file "svm/entry.S"
-#include <xen/lib.h>
-
#include <asm/asm_defns.h>
#include <asm/page.h>
@@ -59,9 +57,6 @@ __UNLIKELY_END(nsvm_hap)
clgi
- ALTERNATIVE "", STR(call vmentry_virt_spec_ctrl), \
- X86_FEATURE_VIRT_SC_MSR_HVM
-
/* WARNING! `ret`, `call *`, `jmp *` not safe beyond this point. */
/* SPEC_CTRL_EXIT_TO_SVM Req: b=curr %rsp=regs/cpuinfo, Clob:
acd */
.macro svm_vmentry_spec_ctrl
@@ -131,9 +126,6 @@ __UNLIKELY_END(nsvm_hap)
ALTERNATIVE "", svm_vmexit_spec_ctrl, X86_FEATURE_SC_MSR_HVM
/* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
- ALTERNATIVE "", STR(call vmexit_virt_spec_ctrl), \
- X86_FEATURE_VIRT_SC_MSR_HVM
-
/*
* STGI is executed unconditionally, and is sufficiently serialising
* to safely resolve any Spectre-v1 concerns in the above logic.
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 53ce2edd35..0849a9dc5f 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -52,7 +52,6 @@
#include <asm/hvm/svm/svmdebug.h>
#include <asm/hvm/svm/nestedsvm.h>
#include <asm/hvm/nestedhvm.h>
-#include <asm/spec_ctrl.h>
#include <asm/x86_emulate.h>
#include <public/sched.h>
#include <asm/hvm/vpt.h>
@@ -611,16 +610,6 @@ static void cf_check svm_cpuid_policy_changed(struct vcpu
*v)
svm_intercept_msr(v, MSR_SPEC_CTRL,
cp->extd.ibrs ? MSR_INTERCEPT_NONE : MSR_INTERCEPT_RW);
- /*
- * Always trap write accesses to VIRT_SPEC_CTRL in order to cache the guest
- * setting and avoid having to perform a rdmsr on vmexit to get the guest
- * setting even if VIRT_SSBD is offered to Xen itself.
- */
- svm_intercept_msr(v, MSR_VIRT_SPEC_CTRL,
- cp->extd.virt_ssbd && cpu_has_virt_ssbd &&
- !cpu_has_amd_ssbd ?
- MSR_INTERCEPT_WRITE : MSR_INTERCEPT_RW);
-
/* Give access to MSR_PRED_CMD if the guest has been told about it. */
svm_intercept_msr(v, MSR_PRED_CMD,
cp->extd.ibpb ? MSR_INTERCEPT_NONE : MSR_INTERCEPT_RW);
@@ -3116,30 +3105,6 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
vmcb_set_vintr(vmcb, intr);
}
-/* Called with GIF=0. */
-void vmexit_virt_spec_ctrl(void)
-{
- unsigned int val = opt_ssbd ? SPEC_CTRL_SSBD : 0;
-
- if ( val == current->arch.msrs->virt_spec_ctrl.raw )
- return;
-
- if ( cpu_has_virt_ssbd )
- wrmsr(MSR_VIRT_SPEC_CTRL, val, 0);
-}
-
-/* Called with GIF=0. */
-void vmentry_virt_spec_ctrl(void)
-{
- unsigned int val = current->arch.msrs->virt_spec_ctrl.raw;
-
- if ( val == (opt_ssbd ? SPEC_CTRL_SSBD : 0) )
- return;
-
- if ( cpu_has_virt_ssbd )
- wrmsr(MSR_VIRT_SPEC_CTRL, val, 0);
-}
-
/*
* Local variables:
* mode: C
diff --git a/xen/arch/x86/include/asm/cpufeatures.h
b/xen/arch/x86/include/asm/cpufeatures.h
index 3895de4faf..672c9ee22b 100644
--- a/xen/arch/x86/include/asm/cpufeatures.h
+++ b/xen/arch/x86/include/asm/cpufeatures.h
@@ -24,7 +24,7 @@ XEN_CPUFEATURE(APERFMPERF, X86_SYNTH( 8)) /*
APERFMPERF */
XEN_CPUFEATURE(MFENCE_RDTSC, X86_SYNTH( 9)) /* MFENCE synchronizes RDTSC
*/
XEN_CPUFEATURE(XEN_SMEP, X86_SYNTH(10)) /* SMEP gets used by Xen
itself */
XEN_CPUFEATURE(XEN_SMAP, X86_SYNTH(11)) /* SMAP gets used by Xen
itself */
-XEN_CPUFEATURE(VIRT_SC_MSR_HVM, X86_SYNTH(12)) /* MSR_VIRT_SPEC_CTRL exposed
to HVM */
+/* Bit 12 - unused. */
XEN_CPUFEATURE(IND_THUNK_LFENCE, X86_SYNTH(13)) /* Use IND_THUNK_LFENCE */
XEN_CPUFEATURE(IND_THUNK_JMP, X86_SYNTH(14)) /* Use IND_THUNK_JMP */
XEN_CPUFEATURE(SC_NO_BRANCH_HARDEN, X86_SYNTH(15)) /* (Disable) Conditional
branch hardening */
diff --git a/xen/arch/x86/include/asm/msr.h b/xen/arch/x86/include/asm/msr.h
index de18e90b2e..ab6fbb5051 100644
--- a/xen/arch/x86/include/asm/msr.h
+++ b/xen/arch/x86/include/asm/msr.h
@@ -375,16 +375,6 @@ struct vcpu_msrs
*/
uint32_t tsc_aux;
- /*
- * 0xc001011f - MSR_VIRT_SPEC_CTRL (if !X86_FEATURE_AMD_SSBD)
- *
- * AMD only. Guest selected value, context switched on guest VM
- * entry/exit.
- */
- struct {
- uint32_t raw;
- } virt_spec_ctrl;
-
/*
* 0xc00110{27,19-1b} MSR_AMD64_DR{0-3}_ADDRESS_MASK
*
diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index 95416995a5..2ae1fcfd5f 100644
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -393,10 +393,7 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t
*val)
if ( !cp->extd.virt_ssbd )
goto gp_fault;
- if ( cpu_has_amd_ssbd )
- *val = msrs->spec_ctrl.raw & SPEC_CTRL_SSBD;
- else
- *val = msrs->virt_spec_ctrl.raw;
+ *val = msrs->spec_ctrl.raw & SPEC_CTRL_SSBD;
break;
case MSR_AMD64_DE_CFG:
@@ -689,15 +686,10 @@ int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t
val)
goto gp_fault;
/* Only supports SSBD bit, the rest are ignored. */
- if ( cpu_has_amd_ssbd )
- {
- if ( val & SPEC_CTRL_SSBD )
- msrs->spec_ctrl.raw |= SPEC_CTRL_SSBD;
- else
- msrs->spec_ctrl.raw &= ~SPEC_CTRL_SSBD;
- }
+ if ( val & SPEC_CTRL_SSBD )
+ msrs->spec_ctrl.raw |= SPEC_CTRL_SSBD;
else
- msrs->virt_spec_ctrl.raw = val & SPEC_CTRL_SSBD;
+ msrs->spec_ctrl.raw &= ~SPEC_CTRL_SSBD;
break;
case MSR_AMD64_DE_CFG:
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index ec44205309..96e7f0983a 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -513,12 +513,9 @@ static void __init print_details(enum ind_thunk thunk,
uint64_t caps)
(boot_cpu_has(X86_FEATURE_SC_MSR_HVM) ||
boot_cpu_has(X86_FEATURE_SC_RSB_HVM) ||
boot_cpu_has(X86_FEATURE_IBPB_ENTRY_HVM) ||
- boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM) ||
opt_eager_fpu || opt_md_clear_hvm) ? "" : "
None",
boot_cpu_has(X86_FEATURE_SC_MSR_HVM) ? " MSR_SPEC_CTRL" : "",
- (boot_cpu_has(X86_FEATURE_SC_MSR_HVM) ||
- boot_cpu_has(X86_FEATURE_VIRT_SC_MSR_HVM)) ? " MSR_VIRT_SPEC_CTRL"
- : "",
+ boot_cpu_has(X86_FEATURE_SC_MSR_HVM) ? " MSR_VIRT_SPEC_CTRL" :
"",
boot_cpu_has(X86_FEATURE_SC_RSB_HVM) ? " RSB" : "",
opt_eager_fpu ? " EAGER_FPU" : "",
opt_md_clear_hvm ? " MD_CLEAR" : "",
@@ -1243,10 +1240,6 @@ void __init init_speculation_mitigations(void)
setup_force_cpu_cap(X86_FEATURE_SC_MSR_HVM);
}
- /* Support VIRT_SPEC_CTRL.SSBD if AMD_SSBD is not available. */
- if ( opt_msr_sc_hvm && !cpu_has_amd_ssbd && cpu_has_virt_ssbd )
- setup_force_cpu_cap(X86_FEATURE_VIRT_SC_MSR_HVM);
-
/* Figure out default_xen_spec_ctrl. */
if ( has_spec_ctrl && ibrs )
{
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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