From 565f4768bb9cf840b2f8cca41483bb91aa3196a3 Mon Sep 17 00:00:00 2001 From: Isaku Yamahata Date: Thu, 29 Feb 2024 01:36:55 -0500 Subject: [PATCH] kvm/tdx: Ignore memory conversion to shared of unassigned region TDX requires vMMIO region to be shared. For KVM, MMIO region is the region which kvm memslot isn't assigned to (except in-kernel emulation). qemu has the memory region for vMMIO at each device level. While OVMF issues MapGPA(to-shared) conservatively on 32bit PCI MMIO region, qemu doesn't find corresponding vMMIO region because it's before PCI device allocation and memory_region_find() finds the device region, not PCI bus region. It's safe to ignore MapGPA(to-shared) because when guest accesses those region they use GPA with shared bit set for vMMIO. Ignore memory conversion request of non-assigned region to shared and return success. Otherwise OVMF is confused and panics there. Signed-off-by: Isaku Yamahata Signed-off-by: Xiaoyao Li Message-ID: <20240229063726.610065-35-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini --- accel/kvm/kvm-all.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 0911154bf8..d7281b93f3 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2923,6 +2923,18 @@ int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private) section = memory_region_find(get_system_memory(), start, size); mr = section.mr; if (!mr) { + /* + * Ignore converting non-assigned region to shared. + * + * TDX requires vMMIO region to be shared to inject #VE to guest. + * OVMF issues conservatively MapGPA(shared) on 32bit PCI MMIO region, + * and vIO-APIC 0xFEC00000 4K page. + * OVMF assigns 32bit PCI MMIO region to + * [top of low memory: typically 2GB=0xC000000, 0xFC00000) + */ + if (!to_private) { + return 0; + } return -1; }