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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: Zhao Liu <zhao1.liu@intel.com>
Subject: [PULL 03/10] target/i386/cpu: Remove unnecessary SGX feature words checks
Date: Wed, 31 Jul 2024 13:17:59 +0200	[thread overview]
Message-ID: <20240731111806.167225-4-pbonzini@redhat.com> (raw)
In-Reply-To: <20240731111806.167225-1-pbonzini@redhat.com>

From: Zhao Liu <zhao1.liu@intel.com>

CPUID.0x7.0.ebx and CPUID.0x7.0.ecx leaves have been expressed as the
feature word lists, and the Host capability support has been checked
in x86_cpu_filter_features().

Therefore, such checks on SGX feature "words" are redundant, and
the follow-up adjustments to those feature "words" will not actually
take effect.

Remove unnecessary SGX feature words related checks.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20240730045544.2516284-2-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index ef06da54c63..a9535284aa9 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6537,8 +6537,6 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
     case 7:
         /* Structured Extended Feature Flags Enumeration Leaf */
         if (count == 0) {
-            uint32_t eax_0_unused, ebx_0, ecx_0, edx_0_unused;
-
             /* Maximum ECX value for sub-leaves */
             *eax = env->cpuid_level_func7;
             *ebx = env->features[FEAT_7_0_EBX]; /* Feature flags */
@@ -6548,20 +6546,8 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             }
             *edx = env->features[FEAT_7_0_EDX]; /* Feature flags */
 
-            /*
-             * SGX cannot be emulated in software.  If hardware does not
-             * support enabling SGX and/or SGX flexible launch control,
-             * then we need to update the VM's CPUID values accordingly.
-             */
-            x86_cpu_get_supported_cpuid(0x7, 0,
-                                        &eax_0_unused, &ebx_0,
-                                        &ecx_0, &edx_0_unused);
-            if ((*ebx & CPUID_7_0_EBX_SGX) && !(ebx_0 & CPUID_7_0_EBX_SGX)) {
-                *ebx &= ~CPUID_7_0_EBX_SGX;
-            }
-
             if ((*ecx & CPUID_7_0_ECX_SGX_LC)
-                    && (!(*ebx & CPUID_7_0_EBX_SGX) || !(ecx_0 & CPUID_7_0_ECX_SGX_LC))) {
+                    && (!(*ebx & CPUID_7_0_EBX_SGX))) {
                 *ecx &= ~CPUID_7_0_ECX_SGX_LC;
             }
         } else if (count == 1) {
-- 
2.45.2



  parent reply	other threads:[~2024-07-31 11:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-31 11:17 [PULL 00/10] i386, tests/vm changes for QEMU 9.1-rc Paolo Bonzini
2024-07-31 11:17 ` [PULL 01/10] tests/vm/openbsd: Install tomli Paolo Bonzini
2024-07-31 11:17 ` [PULL 02/10] target/i386: Change unavail from u32 to u64 Paolo Bonzini
2024-07-31 11:17 ` Paolo Bonzini [this message]
2024-07-31 11:18 ` [PULL 04/10] target/i386/cpu: Explicitly express SGX_LC and SGX feature words dependency Paolo Bonzini
2024-07-31 11:18 ` [PULL 05/10] target/i386/cpu: Add dependencies of CPUID 0x12 leaves Paolo Bonzini
2024-07-31 11:18 ` [PULL 06/10] target/i386/cpu: Mask off SGX/SGX_LC feature words for non-PC machine Paolo Bonzini
2024-07-31 11:18 ` [PULL 07/10] target/i386: Fix typo that assign same value twice Paolo Bonzini
2024-07-31 11:18 ` [PULL 08/10] target/i386: Clean up error cases for vmsr_read_thread_stat() Paolo Bonzini
2024-07-31 11:18 ` [PULL 09/10] qemu-vmsr-helper: fix socket loop breakage Paolo Bonzini
2024-07-31 11:18 ` [PULL 10/10] qemu-vmsr-helper: implement --verbose/-v Paolo Bonzini
2024-08-01  0:00 ` [PULL 00/10] i386, tests/vm changes for QEMU 9.1-rc Richard Henderson

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