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Re: [Qemu-devel] [PATCH 23/31] ich9: implement SMI_LOCK
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 23/31] ich9: implement SMI_LOCK |
Date: |
Mon, 11 May 2015 17:45:17 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 |
On 11/05/2015 17:36, Laszlo Ersek wrote:
> It's not about feature detection -- the question (from
> <address@hidden>) is whether I should set APMC_EN myself
> *every time* before writing to APM_CNT, in the
> EFI_SMM_CONTROL2_PROTOCOL.Trigger() method. That protocol is provided by
> a runtime DXE driver and would be exercised by eg. the non-privileged
> half of the runtime variable service driver.
Oh sorry, I couldn't find that message ID.
> It's no problem to set it, I have the code ready, I was just wondering
> if I should keep that hunk. (In fact it might not even matter: if the OS
> interferes and clears APMC_EN before the non-privileged half mentioned
> above manages to raise the SMI, then the call / transition to SMM will
> simply not happen, which is bad for the OS, and probably irrelevant for
> the firmware (... the security thereof).)
The OS can also race against you and clear APMC_EN, so it's even
unnecessary to reset it.
Paolo
- [Qemu-devel] [PATCH 18/31] q35: fix ESMRAMC default, (continued)
- [Qemu-devel] [PATCH 18/31] q35: fix ESMRAMC default, Paolo Bonzini, 2015/05/11
- [Qemu-devel] [PATCH 19/31] q35: add config space wmask for SMRAM and ESMRAMC, Paolo Bonzini, 2015/05/11
- [Qemu-devel] [PATCH 22/31] q35: implement TSEG, Paolo Bonzini, 2015/05/11
- [Qemu-devel] [PATCH 21/31] q35: add test for SMRAM.D_LCK, Paolo Bonzini, 2015/05/11
- [Qemu-devel] [PATCH 23/31] ich9: implement SMI_LOCK, Paolo Bonzini, 2015/05/11
- Re: [Qemu-devel] [PATCH 23/31] ich9: implement SMI_LOCK, Gerd Hoffmann, 2015/05/12
[Qemu-devel] [PATCH 24/31] hw/acpi: acpi_pm1_cnt_init(): take "disable_s3" and "disable_s4", Paolo Bonzini, 2015/05/11
[Qemu-devel] [PATCH 25/31] hw/acpi: move "etc/system-states" fw_cfg file from PIIX4 to core, Paolo Bonzini, 2015/05/11
[Qemu-devel] [PATCH 26/31] hw/acpi: piix4_pm_init(): take fw_cfg object no more, Paolo Bonzini, 2015/05/11
[Qemu-devel] [PATCH 28/31] vga: disable chain4_alias if KVM supports SMRAM, Paolo Bonzini, 2015/05/11
[Qemu-devel] [PATCH 29/31] pc_piix: rename kvm_enabled to smm_enabled, Paolo Bonzini, 2015/05/11
[Qemu-devel] [PATCH 27/31] target-i386: add support for SMBASE MSR and SMIs, Paolo Bonzini, 2015/05/11
[Qemu-devel] [PATCH 31/31] pc: add SMM property, Paolo Bonzini, 2015/05/11
[Qemu-devel] [PATCH 30/31] ich9: add smm_enabled field and arguments, Paolo Bonzini, 2015/05/11