From: "Laszlo Ersek" <lersek@redhat.com>
To: devel@edk2.groups.io, michael.a.kubacki@intel.com
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Liming Gao <liming.gao@intel.com>,
Jordan Justen <jordan.l.justen@intel.com>,
Hao A Wu <hao.a.wu@intel.com>
Subject: Re: [edk2-devel] [PATCH V3 9/9] OvmfPkg: Disable variable runtime cache
Date: Mon, 14 Oct 2019 20:50:13 +0200 [thread overview]
Message-ID: <aa405122-7da1-397c-787f-6e093c0b536a@redhat.com> (raw)
In-Reply-To: <20191014180846.31660-10-michael.a.kubacki@intel.com>
On 10/14/19 20:08, Kubacki, Michael A wrote:
> Sets gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache
> to FALSE in OvmfPkgIa32.dsc, OvmfPkgIa32X64.dsc, and OvmfPkgX64.dsc
> so that when SMM_REQUIRE is TRUE, the SMM variable driver will not
> use the runtime variable cache.
>
> This is done for OvmfPkg because it currently depends upon a SMM
> variable GetVariable ()implementation as a simple method to exercise
> the SMM driver stack. This allows the following commands to be used
> for variables such as Boot####, BootOrder, and BootNext to test SMM
> timing and stability differences on the BSP (e.g. CPU#0) vs an
> AP (e.g. CPU#1).
> # taskset -c 0 efibootmgr
> # taskset -c 1 efibootmgr
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
> ---
> OvmfPkg/OvmfPkgIa32.dsc | 1 +
> OvmfPkg/OvmfPkgIa32X64.dsc | 1 +
> OvmfPkg/OvmfPkgX64.dsc | 1 +
> 3 files changed, 3 insertions(+)
>
> diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
> index 66e944436a..4861e2342b 100644
> --- a/OvmfPkg/OvmfPkgIa32.dsc
> +++ b/OvmfPkg/OvmfPkgIa32.dsc
> @@ -428,6 +428,7 @@
> !if $(SMM_REQUIRE) == TRUE
> gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire|TRUE
> gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmEnableBspElection|FALSE
> + gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache|FALSE
> !endif
>
> [PcdsFixedAtBuild]
> diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
> index 51c2bfb44f..f316d97d6a 100644
> --- a/OvmfPkg/OvmfPkgIa32X64.dsc
> +++ b/OvmfPkg/OvmfPkgIa32X64.dsc
> @@ -433,6 +433,7 @@
> !if $(SMM_REQUIRE) == TRUE
> gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire|TRUE
> gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmEnableBspElection|FALSE
> + gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache|FALSE
> !endif
>
> [PcdsFixedAtBuild]
> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
> index ba7a758844..546649f0a2 100644
> --- a/OvmfPkg/OvmfPkgX64.dsc
> +++ b/OvmfPkg/OvmfPkgX64.dsc
> @@ -433,6 +433,7 @@
> !if $(SMM_REQUIRE) == TRUE
> gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire|TRUE
> gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmEnableBspElection|FALSE
> + gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache|FALSE
> !endif
>
> [PcdsFixedAtBuild]
>
For this patch:
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
And many thanks for accommodating this use case!
However, I'd prefer the following order of changes:
- patch 7: introduce the PCD with default FALSE value
- patch 9: set the PCD explicitly to FALSE in OvmfPkg
- patch 10 (new patch): flip the PCD default value to TRUE
Because with v3, if someone were to bisect an issue, using OVMF, and the
bisection landed them at patch 7 or at patch 8, they'd see a
(transitory) change in variable caching behavior.
Thanks,
Laszlo
next prev parent reply other threads:[~2019-10-14 18:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-14 18:08 [PATCH V3 0/9] UEFI Variable SMI Reduction Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 1/9] MdeModulePkg/Variable: Consolidate common parsing functions Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 2/9] MdeModulePkg/Variable: Parameterize GetNextVariableInternal () stores Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 3/9] MdeModulePkg/Variable: Parameterize VARIABLE_INFO_ENTRY buffer Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 4/9] MdeModulePkg/Variable: Parameterize auth status in VariableParsing Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 5/9] MdeModulePkg/Variable: Add a file for NV variable functions Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 6/9] MdeModulePkg VariableInfo: Always consider RT DXE and SMM stats Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 7/9] MdeModulePkg/Variable: Add RT GetVariable() cache support Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 8/9] MdeModulePkg/Variable: Add RT GetNextVariableName() " Kubacki, Michael A
2019-10-14 18:08 ` [PATCH V3 9/9] OvmfPkg: Disable variable runtime cache Kubacki, Michael A
2019-10-14 18:50 ` Laszlo Ersek [this message]
2019-10-14 20:57 ` [edk2-devel] " Kubacki, Michael A
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