82 lines
3.2 KiB
Diff
82 lines
3.2 KiB
Diff
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From 52ee6f565f4b4a0ca3325e94dcb44ce68ca61eee Mon Sep 17 00:00:00 2001
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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Mon, 27 Feb 2023 10:41:46 +0100
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Subject: [PATCH] target/i386: KVM: allow fast string operations if host
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supports them
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mainline inclusion
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from mainline-v8.0.0-rc0
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commit 3023c9b4d1092eb27a523c08d9e78cbaec67b59b
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category: feature
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feature: Intel fast REP string operations support
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bugzilla: https://gitee.com/openeuler/intel-qemu/issues/I6ZGIX
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Intel-SIG: commit 3023c9b4d109 ("target/i386: KVM: allow fast string operations if host supports them")
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-------------------------------------
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target/i386: KVM: allow fast string operations if host supports them
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These are just a flag that documents the performance characteristic of
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an instruction; it needs no hypervisor support. So include them even
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if KVM does not show them. In particular, FZRM/FSRS/FSRC have only
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been added very recently, but they are available on Sapphire Rapids
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processors.
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Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: Aichun Shi <aichun.shi@intel.com>
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---
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target/i386/kvm/kvm.c | 17 ++++++++++++++++-
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1 file changed, 16 insertions(+), 1 deletion(-)
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diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
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index b8257e7e5f..6fa3bd9694 100644
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--- a/target/i386/kvm/kvm.c
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+++ b/target/i386/kvm/kvm.c
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@@ -350,7 +350,7 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
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{
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struct kvm_cpuid2 *cpuid;
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uint32_t ret = 0;
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- uint32_t cpuid_1_edx;
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+ uint32_t cpuid_1_edx, unused;
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uint64_t bitmask;
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cpuid = get_supported_cpuid(s);
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@@ -397,10 +397,20 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
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} else if (function == 6 && reg == R_EAX) {
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ret |= CPUID_6_EAX_ARAT; /* safe to allow because of emulated APIC */
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} else if (function == 7 && index == 0 && reg == R_EBX) {
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+ /* Not new instructions, just an optimization. */
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+ uint32_t ebx;
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+ host_cpuid(7, 0, &unused, &ebx, &unused, &unused);
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+ ret |= ebx & CPUID_7_0_EBX_ERMS;
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+
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if (host_tsx_broken()) {
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ret &= ~(CPUID_7_0_EBX_RTM | CPUID_7_0_EBX_HLE);
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}
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} else if (function == 7 && index == 0 && reg == R_EDX) {
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+ /* Not new instructions, just an optimization. */
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+ uint32_t edx;
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+ host_cpuid(7, 0, &unused, &unused, &unused, &edx);
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+ ret |= edx & CPUID_7_0_EDX_FSRM;
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+
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/*
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* Linux v4.17-v4.20 incorrectly return ARCH_CAPABILITIES on SVM hosts.
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* We can detect the bug by checking if MSR_IA32_ARCH_CAPABILITIES is
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@@ -409,6 +419,11 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
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if (!has_msr_arch_capabs) {
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ret &= ~CPUID_7_0_EDX_ARCH_CAPABILITIES;
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}
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+ } else if (function == 7 && index == 1 && reg == R_EAX) {
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+ /* Not new instructions, just an optimization. */
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+ uint32_t eax;
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+ host_cpuid(7, 1, &eax, &unused, &unused, &unused);
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+ ret |= eax & (CPUID_7_1_EAX_FZRM | CPUID_7_1_EAX_FSRS | CPUID_7_1_EAX_FSRC);
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} else if (function == 0xd && index == 0 &&
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(reg == R_EAX || reg == R_EDX)) {
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/*
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--
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2.27.0
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