For supporting VCPU hotplug with SMM enabled/required, QEMU offers the (dynamically detectable) feature called "SMRAM at default SMBASE". When the feature is enabled, the firmware can lock down the 128 KB range starting at the default SMBASE; that is, the [0x3_0000, 0x4_FFFF] interval. The goal is to shield the very first SMI handler of the hotplugged VCPU from OS influence.
Multiple modules in OVMF will have to inter-operate for locking down this range. Introduce a dynamic PCD that will reflect the feature (to be negotiated by PlatformPei), for coordination between drivers. Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> Cc: Jordan Justen <jordan.l.jus...@intel.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1512 Signed-off-by: Laszlo Ersek <ler...@redhat.com> Reviewed-by: Jiewen Yao <jiewen....@intel.com> --- Notes: v2: - trim Cc list - pick up Jiewen's R-b <https://edk2.groups.io/g/devel/message/48166> OvmfPkg/OvmfPkg.dec | 6 ++++++ OvmfPkg/OvmfPkgIa32.dsc | 1 + OvmfPkg/OvmfPkgIa32X64.dsc | 1 + OvmfPkg/OvmfPkgX64.dsc | 1 + 4 files changed, 9 insertions(+) diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec index d5fee805ef4a..57034c784f88 100644 --- a/OvmfPkg/OvmfPkg.dec +++ b/OvmfPkg/OvmfPkg.dec @@ -257,6 +257,12 @@ [PcdsDynamic, PcdsDynamicEx] # This PCD is only accessed if PcdSmmSmramRequire is TRUE (see below). gUefiOvmfPkgTokenSpaceGuid.PcdQ35TsegMbytes|8|UINT16|0x20 + ## Set to TRUE by PlatformPei if the Q35 board supports the "SMRAM at default + # SMBASE" feature. + # + # This PCD is only accessed if PcdSmmSmramRequire is TRUE (see below). + gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase|FALSE|BOOLEAN|0x34 + [PcdsFeatureFlag] gUefiOvmfPkgTokenSpaceGuid.PcdQemuBootOrderPciTranslation|TRUE|BOOLEAN|0x1c gUefiOvmfPkgTokenSpaceGuid.PcdQemuBootOrderMmioTranslation|FALSE|BOOLEAN|0x1d diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc index 4568b78cadf1..43ff51933609 100644 --- a/OvmfPkg/OvmfPkgIa32.dsc +++ b/OvmfPkg/OvmfPkgIa32.dsc @@ -565,6 +565,7 @@ [PcdsDynamicDefault] !if $(SMM_REQUIRE) == TRUE gUefiOvmfPkgTokenSpaceGuid.PcdQ35TsegMbytes|8 + gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase|FALSE gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmSyncMode|0x01 gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmApSyncTimeout|100000 !endif diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc index 152b5d067116..5b3e217e9220 100644 --- a/OvmfPkg/OvmfPkgIa32X64.dsc +++ b/OvmfPkg/OvmfPkgIa32X64.dsc @@ -577,6 +577,7 @@ [PcdsDynamicDefault] !if $(SMM_REQUIRE) == TRUE gUefiOvmfPkgTokenSpaceGuid.PcdQ35TsegMbytes|8 + gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase|FALSE gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmSyncMode|0x01 gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmApSyncTimeout|100000 !endif diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc index 4bfad441bd9f..a378d0a449aa 100644 --- a/OvmfPkg/OvmfPkgX64.dsc +++ b/OvmfPkg/OvmfPkgX64.dsc @@ -576,6 +576,7 @@ [PcdsDynamicDefault] !if $(SMM_REQUIRE) == TRUE gUefiOvmfPkgTokenSpaceGuid.PcdQ35TsegMbytes|8 + gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase|FALSE gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmSyncMode|0x01 gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmApSyncTimeout|100000 !endif -- 2.19.1.3.g30247aa5d201 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#53534): https://edk2.groups.io/g/devel/message/53534 Mute This Topic: https://groups.io/mt/70252351/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
