From: Xin Li <xin3.li@intel.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org
Cc: seanjc@google.com, pbonzini@redhat.com, corbet@lwn.net,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
shuah@kernel.org, vkuznets@redhat.com, peterz@infradead.org,
ravi.v.shankar@intel.com, xin@zytor.com
Subject: [PATCH v2 09/25] KVM: VMX: Switch FRED RSP0 between host and guest
Date: Wed, 7 Feb 2024 09:26:29 -0800 [thread overview]
Message-ID: <20240207172646.3981-10-xin3.li@intel.com> (raw)
In-Reply-To: <20240207172646.3981-1-xin3.li@intel.com>
Switch MSR_IA32_FRED_RSP0 between host and guest in
vmx_prepare_switch_to_{host,guest}().
MSR_IA32_FRED_RSP0 is used during ring 3 event delivery only, thus
KVM, running on ring 0, can run safely with guest FRED RSP0, i.e.,
no need to switch between host/guest FRED RSP0 during VM entry and
exit.
KVM should switch to host FRED RSP0 before returning to user level,
and switch to guest FRED RSP0 before entering guest mode.
Signed-off-by: Xin Li <xin3.li@intel.com>
Tested-by: Shan Kang <shan.kang@intel.com>
---
Changes since v1:
* Don't use guest_cpuid_has() in vmx_prepare_switch_to_{host,guest}(),
which are called from IRQ-disabled context (Chao Gao).
* Reset msr_guest_fred_rsp0 in __vmx_vcpu_reset() (Chao Gao).
---
arch/x86/kvm/vmx/vmx.c | 17 +++++++++++++++++
arch/x86/kvm/vmx/vmx.h | 2 ++
2 files changed, 19 insertions(+)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b7b772183ee4..264378c3b784 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1337,6 +1337,16 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
}
wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
+
+ if (guest_can_use(vcpu, X86_FEATURE_FRED)) {
+ /*
+ * MSR_IA32_FRED_RSP0 is top of task stack, which never changes.
+ * Thus it should be initialized only once.
+ */
+ if (unlikely(vmx->msr_host_fred_rsp0 == 0))
+ vmx->msr_host_fred_rsp0 = read_msr(MSR_IA32_FRED_RSP0);
+ wrmsrl(MSR_IA32_FRED_RSP0, vmx->msr_guest_fred_rsp0);
+ }
#else
savesegment(fs, fs_sel);
savesegment(gs, gs_sel);
@@ -1381,6 +1391,11 @@ static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx)
invalidate_tss_limit();
#ifdef CONFIG_X86_64
wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
+
+ if (guest_can_use(&vmx->vcpu, X86_FEATURE_FRED)) {
+ vmx->msr_guest_fred_rsp0 = read_msr(MSR_IA32_FRED_RSP0);
+ wrmsrl(MSR_IA32_FRED_RSP0, vmx->msr_host_fred_rsp0);
+ }
#endif
load_fixmap_gdt(raw_smp_processor_id());
vmx->guest_state_loaded = false;
@@ -4889,6 +4904,8 @@ static void __vmx_vcpu_reset(struct kvm_vcpu *vcpu)
#ifdef CONFIG_X86_64
if (kvm_cpu_cap_has(X86_FEATURE_FRED)) {
+ vmx->msr_guest_fred_rsp0 = 0;
+
vmcs_write64(GUEST_IA32_FRED_CONFIG, 0);
vmcs_write64(GUEST_IA32_FRED_RSP1, 0);
vmcs_write64(GUEST_IA32_FRED_RSP2, 0);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 3ad52437f426..176ad39be406 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -278,6 +278,8 @@ struct vcpu_vmx {
#ifdef CONFIG_X86_64
u64 msr_host_kernel_gs_base;
u64 msr_guest_kernel_gs_base;
+ u64 msr_host_fred_rsp0;
+ u64 msr_guest_fred_rsp0;
#endif
u64 spec_ctrl;
--
2.43.0
next prev parent reply other threads:[~2024-02-07 17:59 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 17:26 [PATCH v2 00/25] Enable FRED with KVM VMX Xin Li
2024-02-07 17:26 ` [PATCH v2 01/25] KVM: VMX: Cleanup VMX basic information defines and usages Xin Li
2024-02-07 17:26 ` [PATCH v2 02/25] KVM: VMX: Cleanup VMX misc " Xin Li
2024-02-07 17:26 ` [PATCH v2 03/25] KVM: VMX: Add support for the secondary VM exit controls Xin Li
2024-04-19 10:21 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 04/25] KVM: x86: Mark CR4.FRED as not reserved Xin Li
2024-04-19 10:22 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 05/25] KVM: VMX: Initialize FRED VM entry/exit controls in vmcs_config Xin Li
2024-04-19 10:24 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 06/25] KVM: VMX: Defer enabling FRED MSRs save/load until after set CPUID Xin Li
2024-04-19 11:02 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 07/25] KVM: VMX: Set intercept for FRED MSRs Xin Li
2024-04-19 13:35 ` Chao Gao
2024-04-19 17:06 ` Li, Xin3
2024-02-07 17:26 ` [PATCH v2 08/25] KVM: VMX: Initialize VMCS FRED fields Xin Li
2024-04-19 14:01 ` Chao Gao
2024-04-19 17:02 ` Li, Xin3
2024-02-07 17:26 ` Xin Li [this message]
2024-04-19 14:23 ` [PATCH v2 09/25] KVM: VMX: Switch FRED RSP0 between host and guest Chao Gao
2024-04-19 16:37 ` Li, Xin3
2024-02-07 17:26 ` [PATCH v2 10/25] KVM: VMX: Add support for FRED context save/restore Xin Li
2024-04-29 6:31 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 11/25] KVM: x86: Add kvm_is_fred_enabled() Xin Li
2024-04-29 8:24 ` Chao Gao
2024-05-11 1:24 ` Li, Xin3
2024-05-11 1:53 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 12/25] KVM: VMX: Handle FRED event data Xin Li
2024-04-30 3:14 ` Chao Gao
2024-05-10 9:36 ` Li, Xin3
2024-05-11 3:03 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 13/25] KVM: VMX: Handle VMX nested exception for FRED Xin Li
2024-04-30 7:34 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 14/25] KVM: VMX: Disable FRED if FRED consistency checks fail Xin Li
2024-04-30 8:21 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 15/25] KVM: VMX: Dump FRED context in dump_vmcs() Xin Li
2024-04-30 9:09 ` Chao Gao
2024-02-07 17:26 ` [PATCH v2 16/25] KVM: VMX: Invoke vmx_set_cpu_caps() before nested setup Xin Li
2024-02-07 17:26 ` [PATCH v2 17/25] KVM: nVMX: Add support for the secondary VM exit controls Xin Li
2024-02-07 17:26 ` [PATCH v2 18/25] KVM: nVMX: Add a prerequisite to SHADOW_FIELD_R[OW] macros Xin Li
2024-02-07 17:26 ` [PATCH v2 19/25] KVM: nVMX: Add FRED VMCS fields Xin Li
2024-02-07 17:26 ` [PATCH v2 20/25] KVM: nVMX: Add support for VMX FRED controls Xin Li
2024-02-07 17:26 ` [PATCH v2 21/25] KVM: nVMX: Add VMCS FRED states checking Xin Li
2024-02-07 17:26 ` [PATCH v2 22/25] KVM: x86: Allow FRED/LKGS/WRMSRNS to be exposed to guests Xin Li
2024-02-07 17:26 ` [PATCH v2 23/25] KVM: selftests: Run debug_regs test with FRED enabled Xin Li
2024-02-07 17:26 ` [PATCH v2 24/25] KVM: selftests: Add a new VM guest mode to run user level code Xin Li
2024-02-07 17:26 ` [PATCH v2 25/25] KVM: selftests: Add fred exception tests Xin Li
2024-03-29 20:18 ` Muhammad Usama Anjum
2024-03-29 20:18 ` Muhammad Usama Anjum
2024-03-29 20:18 ` Muhammad Usama Anjum
2024-04-24 16:08 ` Sean Christopherson
2024-03-27 8:08 ` [PATCH v2 00/25] Enable FRED with KVM VMX Kang, Shan
2024-04-15 17:58 ` Li, Xin3
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240207172646.3981-10-xin3.li@intel.com \
--to=xin3.li@intel.com \
--cc=bp@alien8.de \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=kvm@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=ravi.v.shankar@intel.com \
--cc=seanjc@google.com \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=x86@kernel.org \
--cc=xin@zytor.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.