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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Wei Liu" <wl@xen.org>, "Jan Beulich" <JBeulich@suse.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [Xen-devel] [PATCH 5/4] x86/svm: Minor cleanup to start_svm()
Date: Thu, 5 Dec 2019 10:51:34 +0000
Message-ID: <20191205105134.7801-1-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <20191204094335.24603-1-andrew.cooper3@citrix.com>

The function is init, so can use boot_cpu_data directly.

There is no need to write 0 to svm_feature_flags in the case of a CPUID
mismatch (not least because this is dead code on real hardware), and no need
to use locked atomic operations.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wl@xen.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/x86/hvm/svm/svm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index af3d45fe56..806bf91171 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1632,14 +1632,14 @@ const struct hvm_function_table * __init start_svm(void)
 
     setup_vmcb_dump();
 
-    svm_feature_flags = (current_cpu_data.extended_cpuid_level >= 0x8000000A ?
-                         cpuid_edx(0x8000000A) : 0);
+    if ( boot_cpu_data.extended_cpuid_level >= 0x8000000a )
+        svm_feature_flags = cpuid_edx(0x8000000a);
 
     printk("SVM: Supported advanced features:\n");
 
     /* DecodeAssists fast paths assume nextrip is valid for fast rIP update. */
     if ( !cpu_has_svm_nrips )
-        clear_bit(SVM_FEATURE_DECODEASSISTS, &svm_feature_flags);
+        __clear_bit(SVM_FEATURE_DECODEASSISTS, &svm_feature_flags);
 
     if ( cpu_has_tsc_ratio )
         svm_function_table.tsc_scaling.ratio_frac_bits = 32;
-- 
2.11.0


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Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-04  9:43 [Xen-devel] [PATCH 0/4] x86/svm: (Post TASK_SWITCH) cleanup Andrew Cooper
2019-12-04  9:43 ` [Xen-devel] [PATCH 1/4] x86/svm: Clean up construct_vmcb() Andrew Cooper
2019-12-04 10:06   ` Jan Beulich
2019-12-04 19:21     ` Andrew Cooper
2019-12-04  9:43 ` [Xen-devel] [PATCH 2/4] x86/svm: Don't shadow variables in svm_vmexit_handler() Andrew Cooper
2019-12-04 10:10   ` Jan Beulich
2019-12-04  9:43 ` [Xen-devel] [PATCH 3/4] x86/svm: Clean up intinfo_t variables Andrew Cooper
2019-12-04 10:19   ` Jan Beulich
2019-12-04 19:22     ` Andrew Cooper
2019-12-04 19:38   ` Andrew Cooper
2019-12-05  9:11     ` Jan Beulich
2019-12-05 12:33   ` Andrew Cooper
2019-12-04  9:43 ` [Xen-devel] [PATCH 4/4] x86/svm: Use named (bit)fields for task switch exit info Andrew Cooper
2019-12-04 10:24   ` Jan Beulich
2019-12-04 20:04     ` Andrew Cooper
2019-12-05  9:05       ` Jan Beulich
2019-12-05 10:51 ` Andrew Cooper [this message]
2019-12-05 10:53   ` [Xen-devel] [PATCH 5/4] x86/svm: Minor cleanup to start_svm() Jan Beulich

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