From: Sean Christopherson <seanjc@google.com>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, linux-efi@vger.kernel.org,
platform-driver-x86@vger.kernel.org, linux-coco@lists.linux.dev,
linux-mm@kvack.org, linux-crypto@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Ard Biesheuvel <ardb@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Dov Murik <dovmurik@linux.ibm.com>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
Borislav Petkov <bp@alien8.de>,
Michael Roth <michael.roth@amd.com>,
Vlastimil Babka <vbabka@suse.cz>,
tony.luck@intel.com, npmccallum@redhat.com,
brijesh.ksingh@gmail.com
Subject: Re: [PATCH Part2 RFC v4 01/40] KVM: SVM: Add support to handle AP reset MSR protocol
Date: Wed, 14 Jul 2021 20:17:29 +0000 [thread overview]
Message-ID: <YO9GWVsZmfXJ4BRl@google.com> (raw)
In-Reply-To: <20210707183616.5620-2-brijesh.singh@amd.com>
On Wed, Jul 07, 2021, Brijesh Singh wrote:
> From: Tom Lendacky <thomas.lendacky@amd.com>
>
> Add support for AP Reset Hold being invoked using the GHCB MSR protocol,
> available in version 2 of the GHCB specification.
Please provide a brief overview of the protocol, and why it's needed. I assume
it's to allow AP wakeup without a shared GHCB?
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
...
> static u8 sev_enc_bit;
> static DECLARE_RWSEM(sev_deactivate_lock);
> static DEFINE_MUTEX(sev_bitmap_lock);
> @@ -2199,6 +2203,9 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
>
> void sev_es_unmap_ghcb(struct vcpu_svm *svm)
> {
> + /* Clear any indication that the vCPU is in a type of AP Reset Hold */
> + svm->ap_reset_hold_type = AP_RESET_HOLD_NONE;
> +
> if (!svm->ghcb)
> return;
>
> @@ -2404,6 +2411,22 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
> GHCB_MSR_INFO_POS);
> break;
> }
> + case GHCB_MSR_AP_RESET_HOLD_REQ:
> + svm->ap_reset_hold_type = AP_RESET_HOLD_MSR_PROTO;
> + ret = kvm_emulate_ap_reset_hold(&svm->vcpu);
The hold type feels like it should be a param to kvm_emulate_ap_reset_hold().
> +
> + /*
> + * Preset the result to a non-SIPI return and then only set
> + * the result to non-zero when delivering a SIPI.
> + */
> + set_ghcb_msr_bits(svm, 0,
> + GHCB_MSR_AP_RESET_HOLD_RESULT_MASK,
> + GHCB_MSR_AP_RESET_HOLD_RESULT_POS);
> +
> + set_ghcb_msr_bits(svm, GHCB_MSR_AP_RESET_HOLD_RESP,
> + GHCB_MSR_INFO_MASK,
> + GHCB_MSR_INFO_POS);
It looks like all uses set an arbitrary value and then the response. I think
folding the response into the helper would improve both readability and robustness.
I also suspect the helper needs to do WRITE_ONCE() to guarantee the guest sees
what it's supposed to see, though memory ordering is not my strong suit.
Might even be able to squeeze in a build-time assertion.
Also, do the guest-provided contents actually need to be preserved? That seems
somewhat odd.
E.g. can it be
static void set_ghcb_msr_response(struct vcpu_svm *svm, u64 response, u64 value,
u64 mask, unsigned int pos)
{
u64 val = (response << GHCB_MSR_INFO_POS) | (val << pos);
WRITE_ONCE(svm->vmcb->control.ghcb_gpa |= (value & mask) << pos;
}
and
set_ghcb_msr_response(svm, GHCB_MSR_AP_RESET_HOLD_RESP,
GHCB_MSR_AP_RESET_HOLD_RESULT_MASK,
GHCB_MSR_AP_RESET_HOLD_RESULT_POS);
> + break;
> case GHCB_MSR_TERM_REQ: {
> u64 reason_set, reason_code;
>
> @@ -2491,6 +2514,7 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
> ret = svm_invoke_exit_handler(vcpu, SVM_EXIT_IRET);
> break;
> case SVM_VMGEXIT_AP_HLT_LOOP:
> + svm->ap_reset_hold_type = AP_RESET_HOLD_NAE_EVENT;
> ret = kvm_emulate_ap_reset_hold(vcpu);
> break;
> case SVM_VMGEXIT_AP_JUMP_TABLE: {
> @@ -2628,13 +2652,29 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
> return;
> }
>
> - /*
> - * Subsequent SIPI: Return from an AP Reset Hold VMGEXIT, where
> - * the guest will set the CS and RIP. Set SW_EXIT_INFO_2 to a
> - * non-zero value.
> - */
> - if (!svm->ghcb)
> - return;
> + /* Subsequent SIPI */
> + switch (svm->ap_reset_hold_type) {
> + case AP_RESET_HOLD_NAE_EVENT:
> + /*
> + * Return from an AP Reset Hold VMGEXIT, where the guest will
> + * set the CS and RIP. Set SW_EXIT_INFO_2 to a non-zero value.
> + */
> + ghcb_set_sw_exit_info_2(svm->ghcb, 1);
> + break;
> + case AP_RESET_HOLD_MSR_PROTO:
> + /*
> + * Return from an AP Reset Hold VMGEXIT, where the guest will
> + * set the CS and RIP. Set GHCB data field to a non-zero value.
> + */
> + set_ghcb_msr_bits(svm, 1,
> + GHCB_MSR_AP_RESET_HOLD_RESULT_MASK,
> + GHCB_MSR_AP_RESET_HOLD_RESULT_POS);
>
> - ghcb_set_sw_exit_info_2(svm->ghcb, 1);
> + set_ghcb_msr_bits(svm, GHCB_MSR_AP_RESET_HOLD_RESP,
> + GHCB_MSR_INFO_MASK,
> + GHCB_MSR_INFO_POS);
> + break;
> + default:
> + break;
> + }
> }
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index 0b89aee51b74..ad12ca26b2d8 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -174,6 +174,7 @@ struct vcpu_svm {
> struct ghcb *ghcb;
> struct kvm_host_map ghcb_map;
> bool received_first_sipi;
> + unsigned int ap_reset_hold_type;
Can't this be a u8?
>
> /* SEV-ES scratch area support */
> void *ghcb_sa;
> --
> 2.17.1
>
next prev parent reply other threads:[~2021-07-14 20:17 UTC|newest]
Thread overview: 178+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-07 18:35 [PATCH Part2 RFC v4 00/40] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 01/40] KVM: SVM: Add support to handle AP reset MSR protocol Brijesh Singh
2021-07-14 20:17 ` Sean Christopherson [this message]
2021-07-15 7:39 ` Joerg Roedel
2021-07-15 13:42 ` Tom Lendacky
2021-07-15 15:45 ` Sean Christopherson
2021-07-15 17:05 ` Tom Lendacky
2021-07-07 18:35 ` [PATCH Part2 RFC v4 02/40] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Brijesh Singh
2021-07-14 20:37 ` Sean Christopherson
2021-07-14 21:00 ` Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 03/40] x86/cpufeatures: Add SEV-SNP CPU feature Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 04/40] x86/sev: Add the host SEV-SNP initialization support Brijesh Singh
2021-07-14 21:07 ` Sean Christopherson
2021-07-14 22:02 ` Brijesh Singh
2021-07-14 22:06 ` Sean Christopherson
2021-07-14 22:11 ` Brijesh Singh
2022-06-02 11:47 ` Jarkko Sakkinen
2022-06-06 11:42 ` Dr. David Alan Gilbert
2021-07-07 18:35 ` [PATCH Part2 RFC v4 05/40] x86/sev: Add RMP entry lookup helpers Brijesh Singh
2021-07-15 18:37 ` Sean Christopherson
2021-07-15 19:28 ` Brijesh Singh
2021-07-16 17:22 ` Brijesh Singh
2021-07-20 22:06 ` Sean Christopherson
2021-07-20 23:10 ` Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 06/40] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Brijesh Singh
2021-07-12 18:44 ` Peter Gonda
2021-07-12 19:00 ` Dave Hansen
2021-07-15 18:56 ` Sean Christopherson
2021-07-15 19:08 ` Dave Hansen
2021-07-15 19:18 ` Sean Christopherson
2021-07-07 18:35 ` [PATCH Part2 RFC v4 07/40] x86/sev: Split the physmap when adding the page in RMP table Brijesh Singh
2021-07-14 22:25 ` Sean Christopherson
2021-07-15 17:05 ` Brijesh Singh
2021-07-15 17:51 ` Sean Christopherson
2021-07-15 18:14 ` Brijesh Singh
2021-07-15 18:39 ` Sean Christopherson
2021-07-15 19:38 ` Brijesh Singh
2021-07-15 22:01 ` Sean Christopherson
2021-07-15 22:11 ` Brijesh Singh
2021-07-30 11:31 ` Vlastimil Babka
2021-07-30 16:10 ` Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 08/40] x86/traps: Define RMP violation #PF error code Brijesh Singh
2021-07-15 19:02 ` Sean Christopherson
2021-07-15 19:16 ` Dave Hansen
2021-07-07 18:35 ` [PATCH Part2 RFC v4 09/40] x86/fault: Add support to dump RMP entry on fault Brijesh Singh
2021-07-07 19:21 ` Dave Hansen
2021-07-08 15:02 ` Brijesh Singh
2021-07-08 15:30 ` Dave Hansen
2021-07-08 16:48 ` Brijesh Singh
2021-07-08 16:58 ` Dave Hansen
2021-07-08 17:11 ` Brijesh Singh
2021-07-08 17:15 ` Dave Hansen
2021-07-07 18:35 ` [PATCH Part2 RFC v4 10/40] x86/fault: Add support to handle the RMP fault for user address Brijesh Singh
2021-07-08 16:16 ` Dave Hansen
2021-07-12 15:43 ` Brijesh Singh
2021-07-12 16:00 ` Dave Hansen
2021-07-12 16:11 ` Brijesh Singh
2021-07-12 16:15 ` Dave Hansen
2021-07-12 16:24 ` Brijesh Singh
2021-07-12 16:29 ` Dave Hansen
2021-07-12 16:49 ` Brijesh Singh
2021-07-15 21:53 ` Sean Christopherson
2021-07-30 16:00 ` Vlastimil Babka
2021-07-30 16:31 ` Dave Hansen
2021-07-07 18:35 ` [PATCH Part2 RFC v4 11/40] crypto:ccp: Define the SEV-SNP commands Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 12/40] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 13/40] crypto: ccp: Shutdown SNP firmware on kexec Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 14/40] crypto:ccp: Provide APIs to issue SEV-SNP commands Brijesh Singh
2021-07-08 18:56 ` Dr. David Alan Gilbert
2021-07-07 18:35 ` [PATCH Part2 RFC v4 15/40] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Brijesh Singh
2021-07-14 13:22 ` Marc Orr
2021-07-14 16:45 ` Brijesh Singh
2021-07-14 18:14 ` Marc Orr
2021-07-15 23:48 ` Sean Christopherson
2021-07-16 12:55 ` Brijesh Singh
2021-07-16 15:35 ` Sean Christopherson
2021-07-16 15:47 ` Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 16/40] crypto: ccp: Handle the legacy SEV command " Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 17/40] crypto: ccp: Add the SNP_PLATFORM_STATUS command Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 18/40] crypto: ccp: Add the SNP_{SET,GET}_EXT_CONFIG command Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 19/40] crypto: ccp: provide APIs to query extended attestation report Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 20/40] KVM: SVM: Make AVIC backing, VMSA and VMCB memory allocation SNP safe Brijesh Singh
2021-07-14 13:35 ` Marc Orr
2021-07-14 16:47 ` Brijesh Singh
2021-07-20 18:02 ` Sean Christopherson
2021-08-03 14:38 ` Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 21/40] KVM: SVM: Add initial SEV-SNP support Brijesh Singh
2021-07-16 18:00 ` Sean Christopherson
2021-07-16 18:46 ` Brijesh Singh
2021-07-16 19:31 ` Sean Christopherson
2021-07-16 21:03 ` Brijesh Singh
2021-07-07 18:35 ` [PATCH Part2 RFC v4 22/40] KVM: SVM: Add KVM_SNP_INIT command Brijesh Singh
2021-07-16 19:33 ` Sean Christopherson
2021-07-16 21:25 ` Brijesh Singh
2021-07-19 20:24 ` Sean Christopherson
2021-07-07 18:35 ` [PATCH Part2 RFC v4 23/40] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Brijesh Singh
2021-07-12 18:45 ` Peter Gonda
2021-07-16 19:43 ` Sean Christopherson
2021-07-16 21:42 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 24/40] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Brijesh Singh
2021-07-16 20:01 ` Sean Christopherson
2021-07-16 22:00 ` Brijesh Singh
2021-07-19 20:51 ` Sean Christopherson
2021-07-19 21:34 ` Brijesh Singh
2021-07-19 21:36 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 25/40] KVM: SVM: Reclaim the guest pages when SEV-SNP VM terminates Brijesh Singh
2021-07-16 20:09 ` Sean Christopherson
2021-07-16 22:16 ` Brijesh Singh
2021-07-17 0:46 ` Sean Christopherson
2021-07-19 12:55 ` Brijesh Singh
2021-07-19 17:18 ` Sean Christopherson
2021-07-19 18:34 ` Brijesh Singh
2021-07-19 19:03 ` Sean Christopherson
2021-07-19 19:14 ` Sean Christopherson
2021-07-19 19:37 ` Brijesh Singh
2021-07-20 16:40 ` Sean Christopherson
2021-07-20 18:23 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 26/40] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Brijesh Singh
2021-07-16 20:18 ` Sean Christopherson
2021-07-16 22:48 ` Brijesh Singh
2021-07-19 16:54 ` Sean Christopherson
2021-07-19 18:29 ` Brijesh Singh
2021-07-19 19:14 ` Sean Christopherson
2021-07-19 19:49 ` Brijesh Singh
2021-07-19 20:13 ` Sean Christopherson
2021-07-21 17:53 ` Marc Orr
2021-07-07 18:36 ` [PATCH Part2 RFC v4 27/40] KVM: X86: Add kvm_x86_ops to get the max page level for the TDP Brijesh Singh
2021-07-16 19:19 ` Sean Christopherson
2021-07-16 20:41 ` Brijesh Singh
2021-07-20 19:38 ` Sean Christopherson
2021-07-20 20:06 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 28/40] KVM: X86: Introduce kvm_mmu_map_tdp_page() for use by SEV Brijesh Singh
2021-07-16 18:15 ` Sean Christopherson
2021-07-07 18:36 ` [PATCH Part2 RFC v4 29/40] KVM: X86: Introduce kvm_mmu_get_tdp_walk() for SEV-SNP use Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 30/40] KVM: X86: Define new RMP check related #NPF error bits Brijesh Singh
2021-07-16 20:22 ` Sean Christopherson
2021-07-17 0:34 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 31/40] KVM: X86: update page-fault trace to log the 64-bit error code Brijesh Singh
2021-07-16 20:25 ` Sean Christopherson
2021-07-17 0:35 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 32/40] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Brijesh Singh
2021-07-16 20:45 ` Sean Christopherson
2021-07-17 0:44 ` Brijesh Singh
2021-07-19 20:04 ` Sean Christopherson
2021-07-07 18:36 ` [PATCH Part2 RFC v4 33/40] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Brijesh Singh
2021-07-16 21:00 ` Sean Christopherson
2021-07-19 14:19 ` Brijesh Singh
2021-07-19 18:55 ` Sean Christopherson
2021-07-19 19:15 ` Brijesh Singh
2021-08-13 16:32 ` Borislav Petkov
2021-07-07 18:36 ` [PATCH Part2 RFC v4 34/40] KVM: SVM: Add support to handle " Brijesh Singh
2021-07-16 21:14 ` Sean Christopherson
2021-07-19 14:24 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 35/40] KVM: Add arch hooks to track the host write to guest memory Brijesh Singh
2021-07-19 23:30 ` Sean Christopherson
2021-07-20 15:15 ` Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 36/40] KVM: X86: Export the kvm_zap_gfn_range() for the SNP use Brijesh Singh
2021-07-07 18:36 ` [PATCH Part2 RFC v4 37/40] KVM: SVM: Add support to handle the RMP nested page fault Brijesh Singh
2021-07-20 0:10 ` Sean Christopherson
2021-07-20 17:55 ` Brijesh Singh
2021-07-20 22:31 ` Sean Christopherson
2021-07-20 23:53 ` Brijesh Singh
2021-07-21 20:15 ` Sean Christopherson
2021-07-07 18:36 ` [PATCH Part2 RFC v4 38/40] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Brijesh Singh
2021-07-19 22:50 ` Sean Christopherson
2021-07-20 14:37 ` Brijesh Singh
2021-07-20 16:28 ` Sean Christopherson
2021-07-20 18:21 ` Brijesh Singh
2021-07-20 22:09 ` Sean Christopherson
2021-07-07 18:36 ` [PATCH Part2 RFC v4 39/40] KVM: SVM: Use a VMSA physical address variable for populating VMCB Brijesh Singh
2021-07-21 0:20 ` Sean Christopherson
2021-07-21 16:26 ` Tom Lendacky
2021-07-07 18:36 ` [PATCH Part2 RFC v4 40/40] KVM: SVM: Support SEV-SNP AP Creation NAE event Brijesh Singh
2021-07-21 0:01 ` Sean Christopherson
2021-07-21 17:47 ` Tom Lendacky
2021-07-21 19:52 ` Sean Christopherson
2021-08-20 14:44 ` Tom Lendacky
2021-07-08 15:40 ` [PATCH Part2 RFC v4 00/40] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Dave Hansen
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