From 43c3df78460dfde11f23c48c9b76f0b81f0d252f Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Wed, 12 Aug 2020 15:21:41 -0500 Subject: [PATCH] OvmfPkg: Reserve a page in memory for the SEV-ES usage BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198 Reserve a fixed area of memory for SEV-ES use and set a fixed PCD, PcdSevEsWorkAreaBase, to this value. This area will be used by SEV-ES support for two purposes: 1. Communicating the SEV-ES status during BSP boot to SEC: Using a byte of memory from the page, the BSP reset vector code can communicate the SEV-ES status to SEC for use before exception handling can be enabled in SEC. After SEC, this field is no longer valid and the standard way of determine if SEV-ES is active should be used. 2. Establishing an area of memory for AP boot support: A hypervisor is not allowed to update an SEV-ES guest's register state, so when booting an SEV-ES guest AP, the hypervisor is not allowed to set the RIP to the guest requested value. Instead an SEV-ES AP must be re-directed from within the guest to the actual requested staring location as specified in the INIT-SIPI-SIPI sequence. Use this memory for reset vector code that can be programmed to have the AP jump to the desired RIP location after starting the AP. This is required for only the very first AP reset. Cc: Jordan Justen Cc: Laszlo Ersek Cc: Ard Biesheuvel Reviewed-by: Laszlo Ersek Signed-off-by: Tom Lendacky Regression-tested-by: Laszlo Ersek --- OvmfPkg/OvmfPkgX64.fdf | 3 +++ 1 file changed, 3 insertions(+) diff --git a/OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf index edb03b5464..8da59037e5 100644 --- a/OvmfPkg/OvmfPkgX64.fdf +++ b/OvmfPkg/OvmfPkgX64.fdf @@ -82,6 +82,9 @@ gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbPageTableBase|gUefiOvmfPkgTokenSpaceGui 0x009000|0x002000 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbSize +0x00B000|0x001000 +gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase|gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize + 0x010000|0x010000 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize -- 2.39.2