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From: Brijesh Singh <brijesh.singh@amd.com>
To: Borislav Petkov <bp@alien8.de>
Cc: brijesh.singh@amd.com, linux-kernel@vger.kernel.org,
	x86@kernel.org, kvm@vger.kernel.org,
	linux-crypto@vger.kernel.org, ak@linux.intel.com,
	herbert@gondor.apana.org.au, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
	"H. Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	David Rientjes <rientjes@google.com>,
	Sean Christopherson <seanjc@google.com>
Subject: Re: [RFC Part2 PATCH 03/30] x86: add helper functions for RMPUPDATE and PSMASH instruction
Date: Thu, 15 Apr 2021 13:15:14 -0500	[thread overview]
Message-ID: <27306231-9cfc-2b98-49ce-ef0a3cdbb683@amd.com> (raw)
In-Reply-To: <20210415180040.GF6318@zn.tnic>


On 4/15/21 1:00 PM, Borislav Petkov wrote:
> On Wed, Mar 24, 2021 at 12:04:09PM -0500, Brijesh Singh wrote:
>> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
>> index 06394b6d56b2..7a0138cb3e17 100644
>> --- a/arch/x86/mm/mem_encrypt.c
>> +++ b/arch/x86/mm/mem_encrypt.c
>> @@ -644,3 +644,44 @@ rmpentry_t *lookup_page_in_rmptable(struct page *page, int *level)
>>  	return entry;
>>  }
>>  EXPORT_SYMBOL_GPL(lookup_page_in_rmptable);
>> +
>> +int rmptable_psmash(struct page *page)
> psmash() should be enough like all those other wrappers around insns.

Noted.


>
>> +{
>> +	unsigned long spa = page_to_pfn(page) << PAGE_SHIFT;
>> +	int ret;
>> +
>> +	if (!static_branch_unlikely(&snp_enable_key))
>> +		return -ENXIO;
>> +
>> +	/* Retry if another processor is modifying the RMP entry. */
> Also, a comment here should say which binutils version supports the
> insn mnemonic so that it can be converted to "psmash" later. Ditto for
> rmpupdate below.
>
> Looking at the binutils repo, it looks like since version 2.36.
>
> /me rebuilds objdump...

Sure, I will add comment.

>> +	do {
>> +		asm volatile(".byte 0xF3, 0x0F, 0x01, 0xFF"
>> +			      : "=a"(ret)
>> +			      : "a"(spa)
>> +			      : "memory", "cc");
>> +	} while (ret == PSMASH_FAIL_INUSE);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(rmptable_psmash);
>> +
>> +int rmptable_rmpupdate(struct page *page, struct rmpupdate *val)
> rmpupdate()
>
>> +{
>> +	unsigned long spa = page_to_pfn(page) << PAGE_SHIFT;
>> +	bool flush = true;
>> +	int ret;
>> +
>> +	if (!static_branch_unlikely(&snp_enable_key))
>> +		return -ENXIO;
>> +
>> +	/* Retry if another processor is modifying the RMP entry. */
>> +	do {
>> +		asm volatile(".byte 0xF2, 0x0F, 0x01, 0xFE"
>> +			     : "=a"(ret)
>> +			     : "a"(spa), "c"((unsigned long)val), "d"(flush)
> 					    ^^^^^^^^^^^^^^^
>
> what's the cast for?
No need to cast it. I will drop in next round.
> "d"(flush)?

Hmm, either it copied this function from pvalidate or old internal APM
may had the flush. I will fix it in the next rev. thanks for pointing it.


>
> There's nothing in the APM talking about RMPUPDATE taking an input arg
> in %rdx?
>

  reply	other threads:[~2021-04-15 18:15 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-24 17:04 [RFC Part2 PATCH 00/30] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 01/30] x86: Add the host SEV-SNP initialization support Brijesh Singh
2021-03-25 14:58   ` Dave Hansen
2021-03-25 15:31     ` Brijesh Singh
2021-03-25 15:51       ` Dave Hansen
2021-03-25 17:41         ` Brijesh Singh
2021-04-14  7:27   ` Borislav Petkov
2021-04-14 22:48     ` Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 02/30] x86/sev-snp: add RMP entry lookup helpers Brijesh Singh
2021-04-15 16:57   ` Borislav Petkov
2021-04-15 18:08     ` Brijesh Singh
2021-04-15 19:50       ` Borislav Petkov
2021-04-15 22:18         ` Brijesh Singh
2021-04-15 17:03   ` Borislav Petkov
2021-04-15 18:09     ` Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 03/30] x86: add helper functions for RMPUPDATE and PSMASH instruction Brijesh Singh
2021-04-15 18:00   ` Borislav Petkov
2021-04-15 18:15     ` Brijesh Singh [this message]
2021-03-24 17:04 ` [RFC Part2 PATCH 04/30] x86/mm: split the physmap when adding the page in RMP table Brijesh Singh
2021-03-25 15:17   ` Dave Hansen
2021-04-19 12:32   ` Borislav Petkov
2021-04-19 15:25     ` Brijesh Singh
2021-04-19 16:52       ` Borislav Petkov
     [not found]         ` <30bff969-e8cf-a991-7660-054ea136855a@amd.com>
2021-04-19 17:58           ` Dave Hansen
2021-04-19 18:10             ` Andy Lutomirski
2021-04-19 18:33               ` Dave Hansen
2021-04-19 18:37                 ` Andy Lutomirski
2021-04-20  9:51                 ` Borislav Petkov
2021-04-19 21:25               ` Brijesh Singh
2021-04-20  9:47           ` Borislav Petkov
2021-03-24 17:04 ` [RFC Part2 PATCH 05/30] x86: define RMP violation #PF error code Brijesh Singh
2021-03-24 18:03   ` Dave Hansen
2021-03-25 14:32     ` Brijesh Singh
2021-03-25 14:34       ` Dave Hansen
2021-04-20 10:32   ` Borislav Petkov
2021-04-20 21:37     ` Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 06/30] x86/fault: dump the RMP entry on #PF Brijesh Singh
2021-03-24 17:47   ` Andy Lutomirski
2021-03-24 20:35     ` Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 07/30] mm: add support to split the large THP based on RMP violation Brijesh Singh
2021-03-25 14:30   ` Dave Hansen
2021-03-25 14:48   ` Dave Hansen
2021-03-25 15:24     ` Brijesh Singh
2021-03-25 15:59       ` Dave Hansen
2021-04-21 12:59         ` Vlastimil Babka
2021-04-21 13:43           ` Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 08/30] crypto:ccp: define the SEV-SNP commands Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 09/30] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 10/30] crypto: ccp: shutdown SNP firmware on kexec Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 11/30] crypto:ccp: provide APIs to issue SEV-SNP commands Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 12/30] crypto ccp: handle the legacy SEV command when SNP is enabled Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 13/30] KVM: SVM: add initial SEV-SNP support Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 14/30] KVM: SVM: make AVIC backing, VMSA and VMCB memory allocation SNP safe Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 15/30] KVM: SVM: define new SEV_FEATURES field in the VMCB Save State Area Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 16/30] KVM: SVM: add KVM_SNP_INIT command Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 17/30] KVM: SVM: add KVM_SEV_SNP_LAUNCH_START command Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 18/30] KVM: SVM: add KVM_SEV_SNP_LAUNCH_UPDATE command Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 19/30] KVM: SVM: Reclaim the guest pages when SEV-SNP VM terminates Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 20/30] KVM: SVM: add KVM_SEV_SNP_LAUNCH_FINISH command Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 21/30] KVM: X86: Add kvm_x86_ops to get the max page level for the TDP Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 22/30] x86/mmu: Introduce kvm_mmu_map_tdp_page() for use by SEV Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 23/30] KVM: X86: Introduce kvm_mmu_get_tdp_walk() for SEV-SNP use Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 24/30] KVM: X86: define new RMP check related #NPF error bits Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 25/30] KVM: X86: update page-fault trace to log the 64-bit error code Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 26/30] KVM: SVM: add support to handle GHCB GPA register VMGEXIT Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 27/30] KVM: SVM: add support to handle MSR based Page State Change VMGEXIT Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 28/30] KVM: SVM: add support to handle " Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 29/30] KVM: X86: export the kvm_zap_gfn_range() for the SNP use Brijesh Singh
2021-03-24 17:04 ` [RFC Part2 PATCH 30/30] KVM: X86: Add support to handle the RMP nested page fault Brijesh Singh

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