From: Yang Weijiang <weijiang.yang@intel.com>
To: seanjc@google.com, pbonzini@redhat.com, dave.hansen@intel.com,
x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, chao.gao@intel.com,
rick.p.edgecombe@intel.com, mlevitsk@redhat.com,
john.allen@amd.com, weijiang.yang@intel.com,
Zhang Yi Z <yi.z.zhang@linux.intel.com>
Subject: [PATCH v10 13/27] KVM: x86: Refresh CPUID on write to guest MSR_IA32_XSS
Date: Sun, 18 Feb 2024 23:47:19 -0800 [thread overview]
Message-ID: <20240219074733.122080-14-weijiang.yang@intel.com> (raw)
In-Reply-To: <20240219074733.122080-1-weijiang.yang@intel.com>
Update CPUID.(EAX=0DH,ECX=1).EBX to reflect current required xstate size
due to XSS MSR modification.
CPUID(EAX=0DH,ECX=1).EBX reports the required storage size of all enabled
xstate features in (XCR0 | IA32_XSS). The CPUID value can be used by guest
before allocate sufficient xsave buffer.
Note, KVM does not yet support any XSS based features, i.e. supported_xss
is guaranteed to be zero at this time.
Opportunistically modify XSS write access logic as:
If XSAVES is not enabled in the guest CPUID, forbid setting IA32_XSS msr
to anything but 0, even if the write is host initiated.
Suggested-by: Sean Christopherson <seanjc@google.com>
Co-developed-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
Signed-off-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 3 ++-
arch/x86/kvm/cpuid.c | 15 ++++++++++++++-
arch/x86/kvm/x86.c | 13 ++++++++++---
3 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f95e93975242..79f7c18c487b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -773,7 +773,6 @@ struct kvm_vcpu_arch {
bool at_instruction_boundary;
bool tpr_access_reporting;
bool xfd_no_write_intercept;
- u64 ia32_xss;
u64 microcode_version;
u64 arch_capabilities;
u64 perf_capabilities;
@@ -829,6 +828,8 @@ struct kvm_vcpu_arch {
u64 xcr0;
u64 guest_supported_xcr0;
+ u64 guest_supported_xss;
+ u64 ia32_xss;
struct kvm_pio_request pio;
void *pio_data;
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 39529e14ae59..2bb1931103ad 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -275,7 +275,8 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_e
best = cpuid_entry2_find(entries, nent, 0xD, 1);
if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
cpuid_entry_has(best, X86_FEATURE_XSAVEC)))
- best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
+ best->ebx = xstate_required_size(vcpu->arch.xcr0 |
+ vcpu->arch.ia32_xss, true);
best = __kvm_find_kvm_cpuid_features(vcpu, entries, nent);
if (kvm_hlt_in_guest(vcpu->kvm) && best &&
@@ -312,6 +313,17 @@ static u64 vcpu_get_supported_xcr0(struct kvm_vcpu *vcpu)
return (best->eax | ((u64)best->edx << 32)) & kvm_caps.supported_xcr0;
}
+static u64 vcpu_get_supported_xss(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best;
+
+ best = kvm_find_cpuid_entry_index(vcpu, 0xd, 1);
+ if (!best)
+ return 0;
+
+ return (best->ecx | ((u64)best->edx << 32)) & kvm_caps.supported_xss;
+}
+
static bool kvm_cpuid_has_hyperv(struct kvm_cpuid_entry2 *entries, int nent)
{
#ifdef CONFIG_KVM_HYPERV
@@ -362,6 +374,7 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
}
vcpu->arch.guest_supported_xcr0 = vcpu_get_supported_xcr0(vcpu);
+ vcpu->arch.guest_supported_xss = vcpu_get_supported_xss(vcpu);
kvm_update_pv_runtime(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9eb5c8dbd4fb..b502d68a2576 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3926,16 +3926,23 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
}
break;
case MSR_IA32_XSS:
- if (!msr_info->host_initiated &&
- !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))
+ /*
+ * If KVM reported support of XSS MSR, even guest CPUID doesn't
+ * support XSAVES, still allow userspace to set default value(0)
+ * to this MSR.
+ */
+ if (!guest_cpuid_has(vcpu, X86_FEATURE_XSAVES) &&
+ !(msr_info->host_initiated && data == 0))
return 1;
/*
* KVM supports exposing PT to the guest, but does not support
* IA32_XSS[bit 8]. Guests have to use RDMSR/WRMSR rather than
* XSAVES/XRSTORS to save/restore PT MSRs.
*/
- if (data & ~kvm_caps.supported_xss)
+ if (data & ~vcpu->arch.guest_supported_xss)
return 1;
+ if (vcpu->arch.ia32_xss == data)
+ break;
vcpu->arch.ia32_xss = data;
kvm_update_cpuid_runtime(vcpu);
break;
--
2.43.0
next prev parent reply other threads:[~2024-02-19 7:47 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-19 7:47 [PATCH v10 00/27] Enable CET Virtualization Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 01/27] x86/fpu/xstate: Always preserve non-user xfeatures/flags in __state_perm Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 02/27] x86/fpu/xstate: Refine CET user xstate bit enabling Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 03/27] x86/fpu/xstate: Add CET supervisor mode state support Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 04/27] x86/fpu/xstate: Introduce XFEATURE_MASK_KERNEL_DYNAMIC xfeature set Yang Weijiang
2024-05-01 18:45 ` Sean Christopherson
2024-05-02 17:46 ` Dave Hansen
2024-05-07 22:57 ` Sean Christopherson
2024-05-07 23:17 ` Dave Hansen
2024-05-08 1:19 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 05/27] x86/fpu/xstate: Introduce fpu_guest_cfg for guest FPU configuration Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 06/27] x86/fpu/xstate: Create guest fpstate with guest specific config Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 07/27] x86/fpu/xstate: Warn if kernel dynamic xfeatures detected in normal fpstate Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 08/27] KVM: x86: Rework cpuid_get_supported_xcr0() to operate on vCPU data Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 09/27] KVM: x86: Rename kvm_{g,s}et_msr()* to menifest emulation operations Yang Weijiang
2024-05-01 18:54 ` Sean Christopherson
2024-05-06 5:58 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 10/27] KVM: x86: Refine xsave-managed guest register/MSR reset handling Yang Weijiang
2024-02-20 3:04 ` Chao Gao
2024-02-20 13:23 ` Yang, Weijiang
2024-05-01 20:40 ` Sean Christopherson
2024-05-06 7:26 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 11/27] KVM: x86: Add kvm_msr_{read,write}() helpers Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 12/27] KVM: x86: Report XSS as to-be-saved if there are supported features Yang Weijiang
2024-02-19 7:47 ` Yang Weijiang [this message]
2024-02-20 8:51 ` [PATCH v10 13/27] KVM: x86: Refresh CPUID on write to guest MSR_IA32_XSS Chao Gao
2024-05-01 20:43 ` Sean Christopherson
2024-05-06 7:30 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 14/27] KVM: x86: Initialize kvm_caps.supported_xss Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 15/27] KVM: x86: Load guest FPU state when access XSAVE-managed MSRs Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 16/27] KVM: x86: Add fault checks for guest CR4.CET setting Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 17/27] KVM: x86: Report KVM supported CET MSRs as to-be-saved Yang Weijiang
2024-05-01 22:40 ` Sean Christopherson
2024-05-06 8:31 ` Yang, Weijiang
2024-05-07 17:27 ` Sean Christopherson
2024-05-08 7:00 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 18/27] KVM: VMX: Introduce CET VMCS fields and control bits Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 19/27] KVM: x86: Use KVM-governed feature framework to track "SHSTK/IBT enabled" Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 20/27] KVM: VMX: Emulate read and write to CET MSRs Yang Weijiang
2024-03-12 22:55 ` Sean Christopherson
2024-03-13 9:43 ` Yang, Weijiang
2024-03-13 16:00 ` Sean Christopherson
2024-02-19 7:47 ` [PATCH v10 21/27] KVM: x86: Save and reload SSP to/from SMRAM Yang Weijiang
2024-05-01 22:50 ` Sean Christopherson
2024-05-06 8:41 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 22/27] KVM: VMX: Set up interception for CET MSRs Yang Weijiang
2024-05-01 23:07 ` Sean Christopherson
2024-05-06 8:48 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 23/27] KVM: VMX: Set host constant supervisor states to VMCS fields Yang Weijiang
2024-02-19 7:47 ` [PATCH v10 24/27] KVM: x86: Enable CET virtualization for VMX and advertise to userspace Yang Weijiang
2024-05-01 23:15 ` Sean Christopherson
2024-05-01 23:24 ` Edgecombe, Rick P
2024-05-06 9:19 ` Yang, Weijiang
2024-05-06 16:54 ` Sean Christopherson
2024-05-07 2:37 ` Yang, Weijiang
2024-05-06 17:05 ` Edgecombe, Rick P
2024-05-06 23:33 ` Sean Christopherson
2024-05-06 23:53 ` Edgecombe, Rick P
2024-05-07 14:21 ` Sean Christopherson
2024-05-07 14:45 ` Edgecombe, Rick P
2024-05-07 15:08 ` Sean Christopherson
2024-05-07 15:33 ` Edgecombe, Rick P
2024-05-16 7:13 ` Yang, Weijiang
2024-05-16 14:39 ` Sean Christopherson
2024-05-16 15:36 ` Dave Hansen
2024-05-16 16:58 ` Sean Christopherson
2024-05-17 8:27 ` Yang, Weijiang
2024-05-17 8:57 ` Thomas Gleixner
2024-05-17 14:26 ` Sean Christopherson
2024-05-20 9:43 ` Yang, Weijiang
2024-05-20 17:09 ` Sean Christopherson
2024-05-20 17:15 ` Dave Hansen
2024-05-22 9:03 ` Yang, Weijiang
2024-05-22 15:06 ` Edgecombe, Rick P
2024-05-23 10:07 ` Yang, Weijiang
2024-05-22 8:41 ` Yang, Weijiang
2024-05-27 9:05 ` Yang, Weijiang
2024-05-01 23:34 ` Sean Christopherson
2024-05-06 9:41 ` Yang, Weijiang
2024-05-16 7:20 ` Yang, Weijiang
2024-05-16 14:43 ` Sean Christopherson
2024-05-17 8:04 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 25/27] KVM: nVMX: Introduce new VMX_BASIC bit for event error_code delivery to L1 Yang Weijiang
2024-05-01 23:19 ` Sean Christopherson
2024-05-06 9:19 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 26/27] KVM: nVMX: Enable CET support for nested guest Yang Weijiang
2024-05-01 23:23 ` Sean Christopherson
2024-05-06 9:25 ` Yang, Weijiang
2024-02-19 7:47 ` [PATCH v10 27/27] KVM: x86: Don't emulate instructions guarded by CET Yang Weijiang
2024-05-01 23:24 ` Sean Christopherson
2024-05-06 9:26 ` Yang, Weijiang
2024-03-06 14:44 ` [PATCH v10 00/27] Enable CET Virtualization Yang, Weijiang
2024-05-01 23:27 ` Sean Christopherson
2024-05-06 9:31 ` Yang, Weijiang
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=20240219074733.122080-14-weijiang.yang@intel.com \
--to=weijiang.yang@intel.com \
--cc=chao.gao@intel.com \
--cc=dave.hansen@intel.com \
--cc=john.allen@amd.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mlevitsk@redhat.com \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=rick.p.edgecombe@intel.com \
--cc=seanjc@google.com \
--cc=x86@kernel.org \
--cc=yi.z.zhang@linux.intel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).