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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	kvm@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>,
	Sean Christopherson <seanjc@google.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>,
	tony.luck@intel.com, npmccallum@redhat.com,
	Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH Part2 RFC v3 06/37] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction
Date: Thu, 10 Jun 2021 14:03:27 +0100	[thread overview]
Message-ID: <YMINnxkDVzRZ8gCQ@work-vm> (raw)
In-Reply-To: <20210602141057.27107-7-brijesh.singh@amd.com>

* Brijesh Singh (brijesh.singh@amd.com) wrote:
> The RMPUPDATE instruction writes a new RMP entry in the RMP Table. The
> hypervisor will use the instruction to add pages to the RMP table. See
> APM3 for details on the instruction operations.
> 
> The PSMASH instruction expands a 2MB RMP entry into a corresponding set of
> contiguous 4KB-Page RMP entries. The hypervisor will use this instruction
> to adjust the RMP entry without invalidating the previous RMP entry.
> 
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  arch/x86/kernel/sev.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/sev.h   | 20 ++++++++++++++++++++
>  2 files changed, 62 insertions(+)
> 
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index 51676ab1a321..9727df945fb1 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -2226,3 +2226,45 @@ struct rmpentry *snp_lookup_page_in_rmptable(struct page *page, int *level)
>  	return entry;
>  }
>  EXPORT_SYMBOL_GPL(snp_lookup_page_in_rmptable);
> +
> +int psmash(struct page *page)
> +{
> +	unsigned long spa = page_to_pfn(page) << PAGE_SHIFT;
> +	int ret;
> +
> +	if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
> +		return -ENXIO;
> +
> +	/* Retry if another processor is modifying the RMP entry. */
> +	do {
> +		/* Binutils version 2.36 supports the PSMASH mnemonic. */
> +		asm volatile(".byte 0xF3, 0x0F, 0x01, 0xFF"
> +			      : "=a"(ret)
> +			      : "a"(spa)
> +			      : "memory", "cc");
> +	} while (ret == FAIL_INUSE);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(psmash);
> +
> +int rmpupdate(struct page *page, struct rmpupdate *val)
> +{
> +	unsigned long spa = page_to_pfn(page) << PAGE_SHIFT;
> +	int ret;
> +
> +	if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
> +		return -ENXIO;
> +
> +	/* Retry if another processor is modifying the RMP entry. */
> +	do {
> +		/* Binutils version 2.36 supports the RMPUPDATE mnemonic. */
> +		asm volatile(".byte 0xF2, 0x0F, 0x01, 0xFE"
> +			     : "=a"(ret)
> +			     : "a"(spa), "c"((unsigned long)val)
> +			     : "memory", "cc");
> +	} while (ret == FAIL_INUSE);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(rmpupdate);
> diff --git a/include/linux/sev.h b/include/linux/sev.h
> index 83c89e999999..bcd4d75d87c8 100644
> --- a/include/linux/sev.h
> +++ b/include/linux/sev.h
> @@ -39,13 +39,33 @@ struct __packed rmpentry {
>  
>  #define RMP_TO_X86_PG_LEVEL(level)	(((level) == RMP_PG_SIZE_4K) ? PG_LEVEL_4K : PG_LEVEL_2M)
>  
> +struct rmpupdate {
> +	u64 gpa;
> +	u8 assigned;
> +	u8 pagesize;
> +	u8 immutable;
> +	u8 rsvd;
> +	u32 asid;
> +} __packed;
> +
> +
> +/*
> + * The psmash() and rmpupdate() returns FAIL_INUSE when another processor is
> + * modifying the RMP entry.
> + */
> +#define FAIL_INUSE              3

Perhaps SEV_FAIL_INUSE ?

(Given that there are a whole buunch of FAIL_* macros already in
general)

Dave

>  #ifdef CONFIG_AMD_MEM_ENCRYPT
>  struct rmpentry *snp_lookup_page_in_rmptable(struct page *page, int *level);
> +int psmash(struct page *page);
> +int rmpupdate(struct page *page, struct rmpupdate *e);
>  #else
>  static inline struct rmpentry *snp_lookup_page_in_rmptable(struct page *page, int *level)
>  {
>  	return NULL;
>  }
> +static inline int psmash(struct page *page) { return -ENXIO; }
> +static inline int rmpupdate(struct page *page, struct rmpupdate *e) { return -ENXIO; }
>  
>  #endif /* CONFIG_AMD_MEM_ENCRYPT */
>  #endif /* __LINUX_SEV_H */
> -- 
> 2.17.1
> 
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK


  reply	other threads:[~2021-06-10 13:03 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-02 14:10 [PATCH Part2 RFC v3 00/37] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 01/37] KVM: SVM: Add support to handle AP reset MSR protocol Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 02/37] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 03/37] x86/cpufeatures: Add SEV-SNP CPU feature Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 04/37] x86/sev: Add the host SEV-SNP initialization support Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 05/37] x86/sev: Add RMP entry lookup helpers Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 06/37] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Brijesh Singh
2021-06-10 13:03   ` Dr. David Alan Gilbert [this message]
2021-06-02 14:10 ` [PATCH Part2 RFC v3 07/37] x86/sev: Split the physmap when adding the page in RMP table Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 08/37] x86/traps: Define RMP violation #PF error code Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 09/37] x86/fault: Add support to dump RMP entry on fault Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 10/37] x86/fault: Add support to handle the RMP fault for user address Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 11/37] crypto:ccp: Define the SEV-SNP commands Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 12/37] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 13/37] crypto: ccp: Shutdown SNP firmware on kexec Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 14/37] crypto:ccp: Provide APIs to issue SEV-SNP commands Brijesh Singh
2021-06-15 11:23   ` Dr. David Alan Gilbert
2021-06-02 14:10 ` [PATCH Part2 RFC v3 15/37] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 16/37] crypto: ccp: Handle the legacy SEV command " Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 17/37] KVM: SVM: make AVIC backing, VMSA and VMCB memory allocation SNP safe Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 18/37] KVM: SVM: Add initial SEV-SNP support Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 19/37] KVM: SVM: Add KVM_SNP_INIT command Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 20/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 21/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 22/37] KVM: SVM: Reclaim the guest pages when SEV-SNP VM terminates Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 23/37] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 24/37] KVM: X86: Add kvm_x86_ops to get the max page level for the TDP Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 25/37] KVM: X86: Introduce kvm_mmu_map_tdp_page() for use by SEV Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 26/37] KVM: X86: Introduce kvm_mmu_get_tdp_walk() for SEV-SNP use Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 27/37] KVM: X86: Define new RMP check related #NPF error bits Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 28/37] KVM: X86: update page-fault trace to log the 64-bit error code Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 29/37] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 30/37] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 31/37] KVM: SVM: Add support to handle " Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 32/37] KVM: Add arch hooks to track the host write to guest memory Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 33/37] KVM: X86: Export the kvm_zap_gfn_range() for the SNP use Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 34/37] KVM: SVM: Add support to handle the RMP nested page fault Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 35/37] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 36/37] KVM: SVM: Use a VMSA physical address variable for populating VMCB Brijesh Singh
2021-06-02 14:10 ` [PATCH Part2 RFC v3 37/37] KVM: SVM: Support SEV-SNP AP Creation NAE event Brijesh Singh

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