From: Dov Murik <dovmurik@linux.ibm.com>
To: Zhi Wang <zhi.wang.linux@gmail.com>, Michael Roth <michael.roth@amd.com>
Cc: kvm@vger.kernel.org, linux-coco@lists.linux.dev,
linux-mm@kvack.org, linux-crypto@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, jroedel@suse.de, thomas.lendacky@amd.com,
hpa@zytor.com, ardb@kernel.org, pbonzini@redhat.com,
seanjc@google.com, vkuznets@redhat.com, jmattson@google.com,
luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com,
pgonda@google.com, peterz@infradead.org,
srinivas.pandruvada@linux.intel.com, rientjes@google.com,
tobin@ibm.com, bp@alien8.de, vbabka@suse.cz,
kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com,
marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com,
alpergun@google.com, dgilbert@redhat.com, jarkko@kernel.org,
ashish.kalra@amd.com, nikunj.dadhania@amd.com,
Brijesh Singh <brijesh.singh@amd.com>,
Dov Murik <dovmurik@linux.ibm.com>
Subject: Re: [PATCH RFC v8 52/56] ccp: Add support to decrypt the page
Date: Thu, 2 Mar 2023 07:59:24 +0200 [thread overview]
Message-ID: <e63ba525-644d-1a8c-afe7-2ced4a8fbb93@linux.ibm.com> (raw)
In-Reply-To: <20230301232045.0000502e@intel.com>
Hi Mike, Zhi,
On 01/03/2023 23:20, Zhi Wang wrote:
> On Mon, 20 Feb 2023 12:38:43 -0600
> Michael Roth <michael.roth@amd.com> wrote:
>
>> From: Brijesh Singh <brijesh.singh@amd.com>
>>
>> Add support to decrypt guest encrypted memory. These API interfaces can
>> be used for example to dump VMCBs on SNP guest exit.
>>
>
> What kinds of check will be applied from firmware when VMM decrypts this
> page? I suppose there has to be kinda mechanism to prevent VMM to decrypt
> any page in the guest. It would be nice to have some introduction about
> it in the comments.
>
The SNP ABI spec says (section 8.27.2 SNP_DBG_DECRYPT):
The firmware checks that the guest's policy allows debugging. If not,
the firmware returns POLICY_FAILURE.
and in the Guest Policy (section 4.3):
Bit 19 - DEBUG
0: Debugging is disallowed.
1: Debugging is allowed.
In the kernel, that firmware error code is defined as
SEV_RET_POLICY_FAILURE.
>> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
>> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
>> [mdr: minor commit fixups]
>> Signed-off-by: Michael Roth <michael.roth@amd.com>
>> ---
>> drivers/crypto/ccp/sev-dev.c | 32 ++++++++++++++++++++++++++++++++
>> include/linux/psp-sev.h | 22 ++++++++++++++++++++--
>> 2 files changed, 52 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
>> index e65563bc8298..bf5167b2acfc 100644
>> --- a/drivers/crypto/ccp/sev-dev.c
>> +++ b/drivers/crypto/ccp/sev-dev.c
>> @@ -2017,6 +2017,38 @@ int sev_guest_df_flush(int *error)
>> }
>> EXPORT_SYMBOL_GPL(sev_guest_df_flush);
>>
>> +int snp_guest_dbg_decrypt_page(u64 gctx_pfn, u64 src_pfn, u64 dst_pfn, int *error)
>> +{
>> + struct sev_data_snp_dbg data = {0};
>> + struct sev_device *sev;
>> + int ret;
>> +
>> + if (!psp_master || !psp_master->sev_data)
>> + return -ENODEV;
>> +
>> + sev = psp_master->sev_data;
>> +
>> + if (!sev->snp_initialized)
>> + return -EINVAL;
>> +
>> + data.gctx_paddr = sme_me_mask | (gctx_pfn << PAGE_SHIFT);
>> + data.src_addr = sme_me_mask | (src_pfn << PAGE_SHIFT);
>> + data.dst_addr = sme_me_mask | (dst_pfn << PAGE_SHIFT);
I guess this works, but I wonder why we need to turn on sme_me_mask on
teh dst_addr. I thought that the firmware decrypts the guest page
(src_addr) to a plaintext page. Couldn't find this requirement in the
SNP spec.
>> +
>> + /* The destination page must be in the firmware state. */
>> + if (rmp_mark_pages_firmware(data.dst_addr, 1, false))
>> + return -EIO;
>> +
>> + ret = sev_do_cmd(SEV_CMD_SNP_DBG_DECRYPT, &data, error);
>> +
>> + /* Restore the page state */
>> + if (snp_reclaim_pages(data.dst_addr, 1, false))
>> + ret = -EIO;
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(snp_guest_dbg_decrypt_page);
>> +
>> int snp_guest_ext_guest_request(struct sev_data_snp_guest_request *data,
>> unsigned long vaddr, unsigned long *npages, unsigned long *fw_err)
>> {
>> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
>> index 81bafc049eca..92116e2b74fd 100644
>> --- a/include/linux/psp-sev.h
>> +++ b/include/linux/psp-sev.h
>> @@ -710,7 +710,6 @@ struct sev_data_snp_dbg {
>> u64 gctx_paddr; /* In */
>> u64 src_addr; /* In */
>> u64 dst_addr; /* In */
>> - u32 len; /* In */
>> } __packed;
The comment above this ^^^ struct still lists the 'len' field, and also
calls the first field 'handle' instead of 'gctx_paddr'.
Also - why is this change happening in this patch? Why was the incorrect
'len' field added in the first place in "[PATCH RFC v8 20/56]
crypto:ccp: Define the SEV-SNP commands" ? (the comment fixes should
probably go there too).
>>
>> /**
>> @@ -913,13 +912,27 @@ int sev_guest_decommission(struct sev_data_decommission *data, int *error);
>> * @error: SEV command return code
>> *
>> * Returns:
>> + * 0 if the sev successfully processed the command
>> + * -%ENODEV if the sev device is not available
>> + * -%ENOTSUPP if the sev does not support SEV
>> + * -%ETIMEDOUT if the sev command timed out
>> + * -%EIO if the sev returned a non-zero return code
>> + */
I think that if the word 'sev' would be 'SEV' in this comment, the diff
will be a bit less misleading (basically this patch should not introduce
changes to sev_do_cmd).
-Dov
>> +int sev_do_cmd(int cmd, void *data, int *psp_ret);
>> +
>> +/**
>> + * snp_guest_dbg_decrypt_page - perform SEV SNP_DBG_DECRYPT command
>> + *
>> + * @sev_ret: sev command return code
>> + *
>> + * Returns:
>> * 0 if the SEV successfully processed the command
>> * -%ENODEV if the SEV device is not available
>> * -%ENOTSUPP if the SEV does not support SEV
>> * -%ETIMEDOUT if the SEV command timed out
>> * -%EIO if the SEV returned a non-zero return code
>> */
>> -int sev_do_cmd(int cmd, void *data, int *psp_ret);
>> +int snp_guest_dbg_decrypt_page(u64 gctx_pfn, u64 src_pfn, u64 dst_pfn, int *error);
>>
>> void *psp_copy_user_blob(u64 uaddr, u32 len);
>> void *snp_alloc_firmware_page(gfp_t mask);
>> @@ -987,6 +1000,11 @@ static inline void *psp_copy_user_blob(u64 __user uaddr, u32 len) { return ERR_P
>>
>> void snp_mark_pages_offline(unsigned long pfn, unsigned int npages) {}
>>
>> +static inline int snp_guest_dbg_decrypt_page(u64 gctx_pfn, u64 src_pfn, u64 dst_pfn, int *error)
>> +{
>> + return -ENODEV;
>> +}
>> +
>> static inline void *snp_alloc_firmware_page(gfp_t mask)
>> {
>> return NULL;
>
next prev parent reply other threads:[~2023-03-02 6:01 UTC|newest]
Thread overview: 147+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-20 18:37 [PATCH RFC v8 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 01/56] KVM: x86: Add 'fault_is_private' x86 op Michael Roth
2023-03-01 10:25 ` Zhi Wang
2023-03-18 4:51 ` Isaku Yamahata
2023-03-20 17:46 ` Michael Roth
2023-03-18 4:53 ` Isaku Yamahata
2023-02-20 18:37 ` [PATCH RFC v8 02/56] KVM: x86: Add 'update_mem_attr' " Michael Roth
2023-03-18 4:56 ` Isaku Yamahata
2023-03-20 18:05 ` Michael Roth
2023-03-21 11:21 ` Zhi Wang
2023-03-22 1:58 ` Michael Roth
2023-03-23 18:17 ` Zhi Wang
2023-03-28 4:36 ` Michael Roth
2023-03-28 23:00 ` Zhi Wang
2023-03-29 23:50 ` Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 03/56] KVM: x86: Add platform hooks for private memory invalidations Michael Roth
2023-03-18 5:13 ` Isaku Yamahata
2023-03-20 18:09 ` Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 04/56] KVM: Add HVA range operator Michael Roth
2023-02-20 21:37 ` Zhi Wang
2023-03-27 0:34 ` Michael Roth
2023-04-04 14:40 ` Zhi Wang
2023-02-20 18:37 ` [PATCH RFC v8 05/56] KVM: SEV: Require KVM_PROTECTED_VM when AMD_MEM_ENCRYPT is enabled Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 06/56] KVM: Split out memory attribute xarray updates to helper function Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 07/56] KVM: SEV: Populate private memory fd during LAUNCH_UPDATE_DATA Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 08/56] KVM: SEV: Rename sev_{pin,unpin}_memory Michael Roth
2023-03-03 14:00 ` Vlastimil Babka
2023-03-06 11:01 ` Nikunj A. Dadhania
2023-02-20 18:38 ` [PATCH RFC v8 09/56] KVM: SEV: Handle memory backed by restricted memfd Michael Roth
2023-03-03 14:05 ` Vlastimil Babka
2023-03-06 11:03 ` Nikunj A. Dadhania
2023-02-20 18:38 ` [PATCH RFC v8 10/56] x86/cpufeatures: Add SEV-SNP CPU feature Michael Roth
2023-02-21 21:21 ` Sathyanarayanan Kuppuswamy
2023-02-22 23:27 ` Kalra, Ashish
2023-02-20 18:38 ` [PATCH RFC v8 11/56] x86/sev: Add the host SEV-SNP initialization support Michael Roth
2023-02-20 20:12 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 12/56] x86/sev: Add RMP entry lookup helpers Michael Roth
2023-03-03 15:28 ` Vlastimil Babka
2023-03-29 22:59 ` Michael Roth
2023-04-20 16:31 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 13/56] x86/fault: Add helper for dumping RMP entries Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 14/56] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 15/56] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Michael Roth
2023-03-01 12:07 ` Tom Dohrmann
2023-03-01 16:15 ` Dave Hansen
2023-03-28 22:12 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 16/56] x86/traps: Define RMP violation #PF error code Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 17/56] x86/fault: Add support to handle the RMP fault for user address Michael Roth
2023-03-01 16:21 ` Dave Hansen
2023-03-28 23:31 ` Michael Roth
2023-04-11 18:27 ` Dave Hansen
2023-03-03 15:31 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 18/56] x86/fault: fix handle_split_page_fault() to work with memfd backed pages Michael Roth
2023-02-20 19:57 ` Hugh Dickins
2023-02-20 20:31 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 19/56] x86/fault: Return pfn from dump_pagetable() for SEV-specific fault handling Michael Roth
2023-02-20 21:13 ` Zhi Wang
2023-02-28 10:53 ` Wu Zongyong
2023-02-20 18:38 ` [PATCH RFC v8 20/56] crypto:ccp: Define the SEV-SNP commands Michael Roth
2023-04-17 14:54 ` Sabin Rapan
2023-02-20 18:38 ` [PATCH RFC v8 21/56] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 22/56] crypto:ccp: Provide API to issue SEV and SNP commands Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 23/56] crypto: ccp: Introduce snp leaked pages list Michael Roth
2023-03-03 15:54 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 24/56] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Michael Roth
2023-02-21 9:28 ` Zhi Wang
2023-02-21 15:31 ` Kalra, Ashish
2023-02-21 21:15 ` Zhi Wang
2023-02-21 22:06 ` Kalra, Ashish
2023-02-20 18:38 ` [PATCH RFC v8 25/56] crypto: ccp: Handle the legacy SEV command " Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 26/56] crypto: ccp: Add the SNP_PLATFORM_STATUS command Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 27/56] crypto: ccp: Add the SNP_{SET,GET}_EXT_CONFIG command Michael Roth
2023-02-22 12:32 ` Zhi Wang
2023-02-22 16:50 ` Tom Lendacky
2023-02-22 22:43 ` Kalra, Ashish
2023-02-23 6:38 ` Zhi Wang
2023-02-23 14:19 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 28/56] crypto: ccp: Provide APIs to query extended attestation report Michael Roth
2023-02-22 20:24 ` Zhi Wang
2023-02-22 22:35 ` Kalra, Ashish
2023-02-23 8:14 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 29/56] KVM: SVM: Add support to handle AP reset MSR protocol Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 30/56] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 31/56] KVM: SVM: Make AVIC backing, VMSA and VMCB memory allocation SNP safe Michael Roth
2023-02-22 20:42 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 32/56] KVM: SVM: Add initial SEV-SNP support Michael Roth
2023-02-23 17:46 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 33/56] KVM: SVM: Add KVM_SNP_INIT command Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 34/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2023-02-23 21:41 ` Zhi Wang
2023-02-24 16:22 ` Tom Lendacky
2023-04-26 17:06 ` Sabin Rapan
2023-04-26 18:02 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 35/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2023-02-24 11:55 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 36/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2023-03-24 14:40 ` Alexander Graf
2023-02-20 18:38 ` [PATCH RFC v8 37/56] KVM: X86: Keep the NPT and RMP page level in sync Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 38/56] KVM: x86: Define RMP page fault error bits for #NPF Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 39/56] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 40/56] KVM: SVM: Add KVM_EXIT_VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 41/56] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2023-02-24 15:06 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 42/56] KVM: SVM: Add support to handle " Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 43/56] KVM: x86: Export the kvm_zap_gfn_range() for the SNP use Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 44/56] KVM: SVM: Add support to handle the RMP nested page fault Michael Roth
2023-02-28 19:11 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 45/56] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2023-02-24 11:01 ` Alexander Graf
2023-02-28 19:34 ` Zhi Wang
2023-04-17 13:05 ` Alexander Graf
2023-02-20 18:38 ` [PATCH RFC v8 46/56] KVM: SVM: Use a VMSA physical address variable for populating VMCB Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 47/56] KVM: SVM: Support SEV-SNP AP Creation NAE event Michael Roth
2023-02-24 12:37 ` Alexander Graf
2023-02-28 20:47 ` Zhi Wang
2023-03-01 21:14 ` Alexander Graf
2023-04-05 0:54 ` Michael Roth
2023-04-04 22:48 ` Michael Roth
2023-04-05 15:20 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 48/56] KVM: SVM: Add SNP-specific handling for memory attribute updates Michael Roth
2023-03-01 23:37 ` Dave Hansen
2023-04-05 23:48 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 49/56] KVM: SVM: Implement .fault_is_private callback for SNP Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 50/56] KVM: SEV: Handle restricted memory invalidations " Michael Roth
2023-03-01 10:41 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 51/56] KVM: SVM: Add module parameter to enable the SEV-SNP Michael Roth
2023-03-01 10:45 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 52/56] ccp: Add support to decrypt the page Michael Roth
2023-03-01 21:20 ` Zhi Wang
2023-03-02 5:59 ` Dov Murik [this message]
2023-03-02 14:33 ` Tom Lendacky
2023-03-02 21:11 ` Dov Murik
2023-02-20 18:38 ` [PATCH RFC v8 53/56] KVM: SVM: Make VMSAVE target area memory allocation SNP safe Michael Roth
2023-03-01 21:23 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 54/56] x86/sev: Add KVM commands for instance certs Michael Roth
2023-02-21 12:40 ` Dov Murik
2023-03-02 0:02 ` Zhi Wang
2023-03-02 1:41 ` Dionna Amalie Glaze
2023-03-02 11:27 ` Zhi Wang
2023-03-02 11:34 ` Dov Murik
2023-02-20 18:38 ` [PATCH RFC v8 55/56] x86/sev: Document KVM_SEV_SNP_{G,S}ET_CERTS Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 56/56] iommu/amd: Add IOMMU_SNP_SHUTDOWN support Michael Roth
2023-03-01 16:56 ` [PATCH RFC v8 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Dave Hansen
2023-03-01 22:59 ` Zhi Wang
2023-03-01 23:39 ` Dave Hansen
2023-08-03 18:27 ` Schander, Johanna 'Mimoja' Amelie
2023-08-04 1:01 ` Kalra, Ashish
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