From: Tianyu Lan <ltykernel@gmail.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
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Subject: Re: [PATCH 05/13] HV: Add Write/Read MSR registers via ghcb page
Date: Mon, 2 Aug 2021 21:18:15 +0800 [thread overview]
Message-ID: <988f20e4-821f-b493-c25d-ca9107a6e891@gmail.com> (raw)
In-Reply-To: <YQfk9G+k0Tj8ihyu@8bytes.org>
On 8/2/2021 8:28 PM, Joerg Roedel wrote:
> On Wed, Jul 28, 2021 at 10:52:20AM -0400, Tianyu Lan wrote:
>> +void hv_ghcb_msr_write(u64 msr, u64 value)
>> +{
>> + union hv_ghcb *hv_ghcb;
>> + void **ghcb_base;
>> + unsigned long flags;
>> +
>> + if (!ms_hyperv.ghcb_base)
>> + return;
>> +
>> + WARN_ON(in_nmi());
>> +
>> + local_irq_save(flags);
>> + ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
>> + hv_ghcb = (union hv_ghcb *)*ghcb_base;
>> + if (!hv_ghcb) {
>> + local_irq_restore(flags);
>> + return;
>> + }
>> +
>> + memset(hv_ghcb, 0x00, HV_HYP_PAGE_SIZE);
>
> Do you really need to zero out the whole 4k? The validation bitmap
> should be enough, there are no secrets on the page anyway.
> Same in hv_ghcb_msr_read().
OK. Thanks for suggestion. I will have a try.
>
>> +enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
>> + struct es_em_ctxt *ctxt,
>> + u64 exit_code, u64 exit_info_1,
>> + u64 exit_info_2)
>> {
>> enum es_result ret;
>>
>> @@ -109,7 +109,16 @@ static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
>> ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
>> ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
>>
>> - sev_es_wr_ghcb_msr(__pa(ghcb));
>> + /*
>> + * Hyper-V runs paravisor with SEV. Ghcb page is allocated by
>> + * paravisor and not needs to be updated in the Linux guest.
>> + * Otherwise, the ghcb page's PA reported by paravisor is above
>> + * VTOM. Hyper-V use this function with NULL for ctxt point and
>> + * skip setting ghcb page in such case.
>> + */
>> + if (ctxt)
>> + sev_es_wr_ghcb_msr(__pa(ghcb));
>
> No, do not make this function work with ctxt==NULL. Instead, factor out
> a helper function which contains what Hyper-V needs and use that in
> sev_es_ghcb_hv_call() and Hyper-V code.
>
OK. Will update.
>> +union hv_ghcb {
>> + struct ghcb ghcb;
>> +} __packed __aligned(PAGE_SIZE);
>
> I am curious what this will end up being good for.
>
Hyper-V introduces a specific hypercall request in GHCB page and use
same union in the Linux Hyper-V code to read/write MSR and call the new
hypercall request.
next prev parent reply other threads:[~2021-08-02 13:18 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-28 14:52 [PATCH 00/13] x86/Hyper-V: Add Hyper-V Isolation VM support Tianyu Lan
2021-07-28 14:52 ` [PATCH 01/13] x86/HV: Initialize GHCB page in Isolation VM Tianyu Lan
2021-08-02 11:53 ` Joerg Roedel
2021-08-02 12:35 ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 02/13] x86/HV: Initialize shared memory boundary in the " Tianyu Lan
2021-07-28 14:52 ` [PATCH 03/13] x86/HV: Add new hvcall guest address host visibility support Tianyu Lan
2021-07-28 15:29 ` Dave Hansen
2021-07-29 12:49 ` Tianyu Lan
2021-08-02 12:01 ` Joerg Roedel
2021-08-02 12:59 ` Tianyu Lan
2021-08-02 13:11 ` Juergen Gross
2021-08-02 13:30 ` Joerg Roedel
2021-07-28 17:06 ` Dave Hansen
2021-07-29 13:01 ` Tianyu Lan
2021-07-29 14:09 ` Dave Hansen
2021-07-29 15:02 ` Tianyu Lan
2021-07-29 16:05 ` Dave Hansen
2021-07-30 2:52 ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 04/13] HV: Mark vmbus ring buffer visible to host in Isolation VM Tianyu Lan
2021-08-02 12:07 ` Joerg Roedel
2021-08-02 12:56 ` Tianyu Lan
2021-08-02 12:59 ` Joerg Roedel
2021-08-02 13:08 ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 05/13] HV: Add Write/Read MSR registers via ghcb page Tianyu Lan
2021-08-02 12:28 ` Joerg Roedel
2021-08-02 13:18 ` Tianyu Lan [this message]
2021-07-28 14:52 ` [PATCH 06/13] HV: Add ghcb hvcall support for SNP VM Tianyu Lan
2021-08-02 12:39 ` Joerg Roedel
2021-08-02 13:32 ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 07/13] HV/Vmbus: Add SNP support for VMbus channel initiate message Tianyu Lan
2021-08-02 12:58 ` Joerg Roedel
2021-07-28 14:52 ` [PATCH 08/13] HV/Vmbus: Initialize VMbus ring buffer for Isolation VM Tianyu Lan
2021-07-28 14:52 ` [PATCH 09/13] DMA: Add dma_map_decrypted/dma_unmap_encrypted() function Tianyu Lan
2021-07-29 15:13 ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 10/13] x86/Swiotlb: Add Swiotlb bounce buffer remap function for HV IVM Tianyu Lan
2021-07-29 16:29 ` Konrad Rzeszutek Wilk
2021-07-30 4:10 ` Tianyu Lan
2021-07-28 14:52 ` [PATCH 11/13] HV/IOMMU: Enable swiotlb bounce buffer for Isolation VM Tianyu Lan
2021-07-28 14:52 ` [PATCH 12/13] HV/Netvsc: Add Isolation VM support for netvsc driver Tianyu Lan
2021-07-28 14:52 ` [PATCH 13/13] HV/Storvsc: Add Isolation VM support for storvsc driver Tianyu Lan
2021-08-02 13:20 ` Joerg Roedel
2021-08-02 14:08 ` Tianyu Lan
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