[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[PATCH 4/5] x86/HVM: drop tsc_scaling.setup() hook


  • To: "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Thu, 16 Nov 2023 14:32:47 +0100
  • Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none
  • Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=bIKEOf7RPr2XJINaMBbAxC+M/xeaOf3qKmLgganWrro=; b=ZMWhybTBRpdojieaW2+PxucipcRqEOuIRzJOYtNhip5i5S0O57PSY6KXii72RDnWpXiNN+sPvccRn+NVMJKBxHB3KPyOWUR5VLjmhc7AyXfFk+BgZBmtKTjMYvLxQZEe1kD42QO1ZOIyZFRv9jVbCrk5Z1PB1DZmGePyo88sNzt6CqYGrw/OP38L6FnVwkg/N0j341pjxQC9zbd9bC2Ivty3Zas8rkIOLeiDNs8gT1f6LG0+ZQNI+8BNLfXJhbBqyUKK60WSUrzGc71kcpEL89MshGwsSc1Dnrhfe+NM5ZqL5MFUbUxoVHIOGyxTmEhZnXQVyZWjOtV1QuqNjJJu5g==
  • Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=fgG/t5S8cqu9/92dBpqjmwC1a1PCcdMTGsyo9ye+tnQhntm9QeN4JbbD3FgBC64jLX1EuGQSFIEHP5mxskI0XZSJmMZIg3RKpLxPr5C5q852YZaty/0kxj8uNCJ/bppvW7Cs2Z9eRSzd/fL6/HSvQuaWwbdz5xx7jAqM3XBWe0h2Q+upKIc17ylBXv+HERLSlitvnECqN3gt6rhUVlhRDZyhzLHxlRgij/IMgUDkGLKTxyg0lXHFh4XEXRWLZMx1HQrhDhCva8LEIbvHj37afEB8iJE3yXY0kq5VFcCpSSFQ1CZqW3ceCFEk+0JZZJ/i/qORDBmBCO5Okze0bHZ2Ug==
  • Authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com;
  • Autocrypt: addr=jbeulich@xxxxxxxx; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL
  • Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Kevin Tian <kevin.tian@xxxxxxxxx>, Jun Nakajima <jun.nakajima@xxxxxxxxx>
  • Delivery-date: Thu, 16 Nov 2023 13:32:54 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

This was used by VMX only, and the intended VMCS write can as well
happen from vmx_set_tsc_offset(), invoked (directly or indirectly)
almost immediately after the present call sites of the hook.
vmx_set_tsc_offset() isn't invoked frequently elsewhere, so the extra
VMCS write shouldn't raise performance concerns.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1086,9 +1086,6 @@ static int cf_check hvm_load_cpu_ctxt(st
     v->arch.hvm.guest_cr[2] = ctxt.cr2;
     hvm_update_guest_cr(v, 2);
 
-    if ( hvm_funcs.tsc_scaling.setup )
-        alternative_vcall(hvm_funcs.tsc_scaling.setup, v);
-
     v->arch.msrs->tsc_aux = ctxt.msr_tsc_aux;
 
     hvm_set_guest_tsc_fixed(v, ctxt.tsc, d->arch.hvm.sync_tsc);
@@ -4033,9 +4030,6 @@ void hvm_vcpu_reset_state(struct vcpu *v
     hvm_set_segment_register(v, x86_seg_gdtr, &reg);
     hvm_set_segment_register(v, x86_seg_idtr, &reg);
 
-    if ( hvm_funcs.tsc_scaling.setup )
-        alternative_vcall(hvm_funcs.tsc_scaling.setup, v);
-
     /* Sync AP's TSC with BSP's. */
     v->arch.hvm.cache_tsc_offset =
         v->domain->vcpu[0]->arch.hvm.cache_tsc_offset;
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1454,20 +1454,13 @@ static void cf_check vmx_handle_cd(struc
     }
 }
 
-static void cf_check vmx_setup_tsc_scaling(struct vcpu *v)
-{
-    if ( v->domain->arch.vtsc )
-        return;
-
-    vmx_vmcs_enter(v);
-    __vmwrite(TSC_MULTIPLIER, hvm_tsc_scaling_ratio(v->domain));
-    vmx_vmcs_exit(v);
-}
-
 static void cf_check vmx_set_tsc_offset(struct vcpu *v, u64 offset, u64 at_tsc)
 {
     vmx_vmcs_enter(v);
 
+    if ( !v->domain->arch.vtsc && cpu_has_vmx_tsc_scaling )
+        __vmwrite(TSC_MULTIPLIER, hvm_tsc_scaling_ratio(v->domain));
+
     if ( nestedhvm_vcpu_in_guestmode(v) )
         offset += nvmx_get_tsc_offset(v);
 
@@ -3030,10 +3023,7 @@ const struct hvm_function_table * __init
     }
 
     if ( cpu_has_vmx_tsc_scaling )
-    {
         vmx_function_table.tsc_scaling.ratio_frac_bits = 48;
-        vmx_function_table.tsc_scaling.setup = vmx_setup_tsc_scaling;
-    }
 
     model_specific_lbr = get_model_specific_lbr();
     lbr_tsx_fixup_check();
--- a/xen/arch/x86/include/asm/hvm/hvm.h
+++ b/xen/arch/x86/include/asm/hvm/hvm.h
@@ -240,9 +240,6 @@ struct hvm_function_table {
         uint8_t  ratio_frac_bits;
         /* maximum-allowed TSC scaling ratio */
         uint64_t max_ratio;
-
-        /* Architecture function to setup TSC scaling ratio */
-        void (*setup)(struct vcpu *v);
     } tsc_scaling;
 };
 




 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.