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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 06/10] x86/spec_ctrl: Split X86_FEATURE_SC_MSR into PV and HVM variants
In order to separately control whether MSR_SPEC_CTRL is virtualised for PV and
HVM guests, split the feature used to control runtime alternatives into two.
Xen will use MSR_SPEC_CTRL itself if either of these features are active.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Juergen Gross <jgross@xxxxxxxx>
---
xen/arch/x86/spec_ctrl.c | 6 ++++--
xen/include/asm-x86/cpufeatures.h | 3 ++-
xen/include/asm-x86/spec_ctrl.h | 8 ++++++--
xen/include/asm-x86/spec_ctrl_asm.h | 12 ++++++------
4 files changed, 18 insertions(+), 11 deletions(-)
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index f489f79..0404962 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -128,7 +128,8 @@ static void __init print_details(enum ind_thunk thunk,
uint64_t caps)
thunk == THUNK_RETPOLINE ? "RETPOLINE" :
thunk == THUNK_LFENCE ? "LFENCE" :
thunk == THUNK_JMP ? "JMP" : "?",
- boot_cpu_has(X86_FEATURE_SC_MSR) ?
+ (boot_cpu_has(X86_FEATURE_SC_MSR_PV) ||
+ boot_cpu_has(X86_FEATURE_SC_MSR_HVM)) ?
default_xen_spec_ctrl & SPEC_CTRL_IBRS ? " IBRS+" :
" IBRS-" : "",
opt_ibpb ? " IBPB" : "",
@@ -367,7 +368,8 @@ void __init init_speculation_mitigations(void)
* need the IBRS entry/exit logic to virtualise IBRS support for
* guests.
*/
- setup_force_cpu_cap(X86_FEATURE_SC_MSR);
+ setup_force_cpu_cap(X86_FEATURE_SC_MSR_PV);
+ setup_force_cpu_cap(X86_FEATURE_SC_MSR_HVM);
if ( ibrs )
default_xen_spec_ctrl |= SPEC_CTRL_IBRS;
diff --git a/xen/include/asm-x86/cpufeatures.h
b/xen/include/asm-x86/cpufeatures.h
index f9aa5d7..9d5d81e 100644
--- a/xen/include/asm-x86/cpufeatures.h
+++ b/xen/include/asm-x86/cpufeatures.h
@@ -26,7 +26,8 @@ XEN_CPUFEATURE(LFENCE_DISPATCH, (FSCAPINTS+0)*32+12) /*
lfence set as Dispatch S
XEN_CPUFEATURE(IND_THUNK_LFENCE,(FSCAPINTS+0)*32+13) /* Use IND_THUNK_LFENCE */
XEN_CPUFEATURE(IND_THUNK_JMP, (FSCAPINTS+0)*32+14) /* Use IND_THUNK_JMP */
XEN_CPUFEATURE(XEN_IBPB, (FSCAPINTS+0)*32+15) /* IBRSB || IBPB */
-XEN_CPUFEATURE(SC_MSR, (FSCAPINTS+0)*32+16) /* MSR_SPEC_CTRL used by
Xen */
+XEN_CPUFEATURE(SC_MSR_PV, (FSCAPINTS+0)*32+16) /* MSR_SPEC_CTRL used by
Xen for PV */
+XEN_CPUFEATURE(SC_MSR_HVM, (FSCAPINTS+0)*32+17) /* MSR_SPEC_CTRL used by
Xen for HVM */
XEN_CPUFEATURE(SC_RSB_PV, (FSCAPINTS+0)*32+18) /* RSB overwrite needed
for PV */
XEN_CPUFEATURE(SC_RSB_HVM, (FSCAPINTS+0)*32+19) /* RSB overwrite needed
for HVM */
XEN_CPUFEATURE(NO_XPTI, (FSCAPINTS+0)*32+20) /* XPTI mitigation not in
use */
diff --git a/xen/include/asm-x86/spec_ctrl.h b/xen/include/asm-x86/spec_ctrl.h
index 86a3dfe..9880e19 100644
--- a/xen/include/asm-x86/spec_ctrl.h
+++ b/xen/include/asm-x86/spec_ctrl.h
@@ -56,7 +56,9 @@ static always_inline void spec_ctrl_enter_idle(struct
cpu_info *info)
barrier();
info->spec_ctrl_flags |= SCF_use_shadow;
barrier();
- asm volatile ( ALTERNATIVE(ASM_NOP3, "wrmsr", X86_FEATURE_SC_MSR)
+ asm volatile ( ALTERNATIVE_2(ASM_NOP3,
+ "wrmsr", X86_FEATURE_SC_MSR_PV,
+ "wrmsr", X86_FEATURE_SC_MSR_HVM)
:: "a" (val), "c" (MSR_SPEC_CTRL), "d" (0) : "memory" );
}
@@ -71,7 +73,9 @@ static always_inline void spec_ctrl_exit_idle(struct cpu_info
*info)
*/
info->spec_ctrl_flags &= ~SCF_use_shadow;
barrier();
- asm volatile ( ALTERNATIVE(ASM_NOP3, "wrmsr", X86_FEATURE_SC_MSR)
+ asm volatile ( ALTERNATIVE_2(ASM_NOP3,
+ "wrmsr", X86_FEATURE_SC_MSR_PV,
+ "wrmsr", X86_FEATURE_SC_MSR_HVM)
:: "a" (val), "c" (MSR_SPEC_CTRL), "d" (0) : "memory" );
}
diff --git a/xen/include/asm-x86/spec_ctrl_asm.h
b/xen/include/asm-x86/spec_ctrl_asm.h
index bf36b5a..edace2a 100644
--- a/xen/include/asm-x86/spec_ctrl_asm.h
+++ b/xen/include/asm-x86/spec_ctrl_asm.h
@@ -223,34 +223,34 @@
#define SPEC_CTRL_ENTRY_FROM_HVM \
ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_HVM; \
ALTERNATIVE "", DO_SPEC_CTRL_ENTRY_FROM_HVM, \
- X86_FEATURE_SC_MSR
+ X86_FEATURE_SC_MSR_HVM
/* Use after an entry from PV context (syscall/sysenter/int80/int82/etc). */
#define SPEC_CTRL_ENTRY_FROM_PV \
ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV; \
ALTERNATIVE "", __stringify(DO_SPEC_CTRL_ENTRY maybexen=0), \
- X86_FEATURE_SC_MSR
+ X86_FEATURE_SC_MSR_PV
/* Use in interrupt/exception context. May interrupt Xen or PV context. */
#define SPEC_CTRL_ENTRY_FROM_INTR \
ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_SC_RSB_PV; \
ALTERNATIVE "", __stringify(DO_SPEC_CTRL_ENTRY maybexen=1), \
- X86_FEATURE_SC_MSR
+ X86_FEATURE_SC_MSR_PV
/* Use when exiting to Xen context. */
#define SPEC_CTRL_EXIT_TO_XEN \
ALTERNATIVE "", \
- DO_SPEC_CTRL_EXIT_TO_XEN, X86_FEATURE_SC_MSR
+ DO_SPEC_CTRL_EXIT_TO_XEN, X86_FEATURE_SC_MSR_PV
/* Use when exiting to PV guest context. */
#define SPEC_CTRL_EXIT_TO_PV \
ALTERNATIVE "", \
- DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR
+ DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR_PV
/* Use when exiting to HVM guest context. */
#define SPEC_CTRL_EXIT_TO_HVM \
ALTERNATIVE "", \
- DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR
+ DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_SC_MSR_HVM
/*
* Use in IST interrupt/exception context. May interrupt Xen or PV context.
--
2.1.4
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