Re: [PATCH v7 16/45] x86/sev: Register GHCB memory when SEV-SNP is active
From: Borislav Petkov <bp@alien8.de>
Date: 2021-12-08 17:41:55
Also in:
kvm, linux-coco, linux-efi, lkml, platform-driver-x86
On Wed, Nov 10, 2021 at 04:07:02PM -0600, Brijesh Singh wrote:
The SEV-SNP guest is required to perform GHCB GPA registration. This is because the hypervisor may prefer that a guest use a consistent and/or specific GPA for the GHCB associated with a vCPU. For more information, see the GHCB specification section GHCB GPA Registration. During the boot, init_ghcb() allocates a per-cpu GHCB page. On very first VC exception,
That is not true anymore - you're doing proper init at init time - no more #VC hackery.
quoted hunk ↗ jump to hunk
@@ -1977,6 +1978,10 @@ void cpu_init_exception_handling(void) load_TR_desc(); + /* Register the GHCB before taking any VC exception */ + if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))
No need for that if branch - sev_snp_register_ghcb() already has an empty stub for the !CONFIG_AMD_MEM_ENCRYPT case so you can simply call it unconditionally.
quoted hunk ↗ jump to hunk
+ sev_snp_register_ghcb(); + /* Finally load the IDT */ load_current_idt(); }diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 54bf0603002f..968105cec364 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c@@ -588,6 +588,9 @@ void early_setup_idt(void) bringup_idt_descr.address = (unsigned long)bringup_idt_table; native_load_idt(&bringup_idt_descr); + + if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) + sev_snp_register_ghcb();
Ditto.
Thx.
--
Regards/Gruss,
Boris.
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