From: Paolo Bonzini <pbonzini@redhat.com>
To: Yang Weijiang <weijiang.yang@intel.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
sean.j.christopherson@intel.com, jmattson@google.com
Cc: yu.c.zhang@linux.intel.com
Subject: Re: [PATCH v14 08/13] KVM: VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP
Date: Thu, 28 Jan 2021 18:42:31 +0100 [thread overview]
Message-ID: <f94b472f-086e-ea0c-5ff0-848d5a9689dc@redhat.com> (raw)
In-Reply-To: <20201106011637.14289-9-weijiang.yang@intel.com>
On 06/11/20 02:16, Yang Weijiang wrote:
> Introduce a host-only synthetic MSR, MSR_KVM_GUEST_SSP so that the VMM
> can read/write the guest's SSP, e.g. to migrate CET state. Use a
> synthetic MSR, e.g. as opposed to a VCPU_REG_, as GUEST_SSP is subject
> to the same consistency checks as the PL*_SSP MSRs, i.e. can share code.
>
> Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> ---
> arch/x86/include/uapi/asm/kvm_para.h | 1 +
> arch/x86/kvm/vmx/vmx.c | 14 ++++++++++++--
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
> index 812e9b4c1114..5203dc084125 100644
> --- a/arch/x86/include/uapi/asm/kvm_para.h
> +++ b/arch/x86/include/uapi/asm/kvm_para.h
> @@ -53,6 +53,7 @@
> #define MSR_KVM_POLL_CONTROL 0x4b564d05
> #define MSR_KVM_ASYNC_PF_INT 0x4b564d06
> #define MSR_KVM_ASYNC_PF_ACK 0x4b564d07
> +#define MSR_KVM_GUEST_SSP 0x4b564d08
>
> struct kvm_steal_time {
> __u64 steal;
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index dd78d3a79e79..28ba8414a7a3 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -1817,7 +1817,8 @@ static bool cet_is_ssp_msr_accessible(struct kvm_vcpu *vcpu,
> if (msr->host_initiated)
> return true;
>
> - if (!guest_cpuid_has(vcpu, X86_FEATURE_SHSTK))
> + if (!guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) ||
> + msr->index == MSR_KVM_GUEST_SSP)
> return false;
>
> if (msr->index == MSR_IA32_INT_SSP_TAB)
> @@ -1995,6 +1996,11 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> return 1;
> msr_info->data = vmcs_readl(GUEST_INTR_SSP_TABLE);
> break;
> + case MSR_KVM_GUEST_SSP:
> + if (!cet_is_ssp_msr_accessible(vcpu, msr_info))
> + return 1;
> + msr_info->data = vmcs_readl(GUEST_SSP);
> + break;
> case MSR_IA32_PL0_SSP ... MSR_IA32_PL3_SSP:
> if (!cet_is_ssp_msr_accessible(vcpu, msr_info))
> return 1;
> @@ -2287,12 +2293,16 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> return 1;
> vmcs_writel(GUEST_INTR_SSP_TABLE, data);
> break;
> + case MSR_KVM_GUEST_SSP:
> case MSR_IA32_PL0_SSP ... MSR_IA32_PL3_SSP:
> if (!cet_is_ssp_msr_accessible(vcpu, msr_info))
> return 1;
> if ((data & GENMASK(2, 0)) || is_noncanonical_address(data, vcpu))
> return 1;
> - vmx_set_xsave_msr(msr_info);
> + if (msr_index == MSR_KVM_GUEST_SSP)
> + vmcs_writel(GUEST_SSP, data);
> + else
> + vmx_set_xsave_msr(msr_info);
> break;
> case MSR_TSC_AUX:
> if (!msr_info->host_initiated &&
>
Doh, I misread the change in cet_is_ssp_msr_accessible, sorry. */
next prev parent reply other threads:[~2021-01-28 17:44 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-06 1:16 [PATCH v14 00/13] Introduce support for guest CET feature Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 01/13] KVM: x86: Report XSS as an MSR to be saved if there are supported features Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 02/13] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 03/13] KVM: x86: Add #CP support in guest exception dispatch Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 04/13] KVM: VMX: Introduce CET VMCS fields and flags Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 05/13] KVM: x86: Add fault checks for CR4.CET Yang Weijiang
2020-11-09 10:44 ` kernel test robot
2020-11-06 1:16 ` [PATCH v14 06/13] KVM: x86: Load guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 07/13] KVM: VMX: Emulate reads and writes to CET MSRs Yang Weijiang
2021-01-28 17:45 ` Paolo Bonzini
2021-01-29 8:07 ` Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 08/13] KVM: VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP Yang Weijiang
2021-01-28 17:41 ` Paolo Bonzini
2021-01-28 17:42 ` Paolo Bonzini [this message]
2020-11-06 1:16 ` [PATCH v14 09/13] KVM: x86: Report CET MSRs as to-be-saved if CET is supported Yang Weijiang
2021-01-28 17:46 ` Paolo Bonzini
2021-01-29 8:08 ` Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 10/13] KVM: x86: Enable CET virtualization for VMX and advertise CET to userspace Yang Weijiang
2020-11-09 7:23 ` kernel test robot
2021-01-28 17:53 ` Paolo Bonzini
[not found] ` <20210129112437.GA29715@local-michael-cet-test.sh.intel.com>
[not found] ` <68e288ee-6e09-36f1-a6c9-bed864eb7678@redhat.com>
[not found] ` <20210129121717.GA30243@local-michael-cet-test.sh.intel.com>
[not found] ` <1cf7e501-2c69-8b76-9332-42db1348ab08@redhat.com>
2021-01-30 6:32 ` Yang Weijiang
2021-02-01 4:56 ` Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 11/13] KVM: VMX: Pass through CET MSRs to the guest when supported Yang Weijiang
2021-01-28 17:54 ` Paolo Bonzini
2021-01-28 18:04 ` Paolo Bonzini
2020-11-06 1:16 ` [PATCH v14 12/13] KVM: nVMX: Add helper to check the vmcs01 MSR bitmap for MSR pass-through Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 13/13] KVM: nVMX: Enable CET support for nested VMX Yang Weijiang
2021-01-28 17:57 ` [PATCH v14 00/13] Introduce support for guest CET feature Paolo Bonzini
2021-01-28 18:04 ` Sean Christopherson
2021-01-28 18:06 ` Paolo Bonzini
2021-01-28 18:24 ` Sean Christopherson
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=f94b472f-086e-ea0c-5ff0-848d5a9689dc@redhat.com \
--to=pbonzini@redhat.com \
--cc=jmattson@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=sean.j.christopherson@intel.com \
--cc=weijiang.yang@intel.com \
--cc=yu.c.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 NNTP newsgroup(s).