| Message ID | 20230505071117.369471-2-kraxel@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | misc tweaks for kvm and the 64bit pci window | expand |
On Fri, May 05, 2023 at 09:11:12AM +0200, Gerd Hoffmann wrote: > > In case kvm emulates features of another hypervisor (for example hyperv) > two VMM CPUID blocks will be present, one for the emulated hypervisor > and one for kvm itself. > > This patch makes seabios loop over the VMM CPUID blocks to make sure it > will properly detect kvm when multiple blocks are present. > > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> This patch forgot to adapt the kvmclock code to also use the detected kvm cpuid base. Updated patch below. take care, Gerd ------------------------ ✂️ cut here ------------------------- From 8548ec47c68e198d75e174f82db9959eebb701be Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann <kraxel@redhat.com> Date: Fri, 9 Sep 2022 07:45:13 +0200 Subject: [PATCH 1/6] better kvm detection In case kvm emulates features of another hypervisor (for example hyperv) two VMM CPUID blocks will be present, one for the emulated hypervisor and one for kvm itself. This patch makes seabios loop over the VMM CPUID blocks to make sure it will properly detect kvm when multiple blocks are present. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> --- src/fw/paravirt.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c index fba4e52db684..42abac8460c5 100644 --- a/src/fw/paravirt.c +++ b/src/fw/paravirt.c @@ -53,23 +53,35 @@ inline int qemu_cfg_dma_enabled(void) * should be used to determine that a VM is running under KVM. */ #define KVM_CPUID_SIGNATURE 0x40000000 +static unsigned int kvm_cpuid_base = 0; static void kvm_detect(void) { + unsigned int i, max = 0; unsigned int eax, ebx, ecx, edx; char signature[13]; - cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx); - memcpy(signature + 0, &ebx, 4); - memcpy(signature + 4, &ecx, 4); - memcpy(signature + 8, &edx, 4); - signature[12] = 0; + for (i = KVM_CPUID_SIGNATURE;; i += 0x100) { + eax = 0; + cpuid(i, &eax, &ebx, &ecx, &edx); + if (eax < i) + break; + memcpy(signature + 0, &ebx, 4); + memcpy(signature + 4, &ecx, 4); + memcpy(signature + 8, &edx, 4); + signature[12] = 0; + dprintf(1, "cpuid 0x%x: eax %x, signature '%s'\n", i, eax, signature); + if (strcmp(signature, "KVMKVMKVM") == 0) { + kvm_cpuid_base = i; + max = eax; + } + } - if (strcmp(signature, "KVMKVMKVM") == 0) { + if (kvm_cpuid_base) { dprintf(1, "Running on KVM\n"); PlatformRunningOn |= PF_KVM; - if (eax >= KVM_CPUID_SIGNATURE + 0x10) { - cpuid(KVM_CPUID_SIGNATURE + 0x10, &eax, &ebx, &ecx, &edx); + if (max >= kvm_cpuid_base + 0x10) { + cpuid(kvm_cpuid_base + 0x10, &eax, &ebx, &ecx, &edx); dprintf(1, "kvm: have invtsc, freq %u kHz\n", eax); tsctimer_setfreq(eax, "invtsc"); } @@ -93,7 +105,7 @@ static void kvmclock_init(void) if (!runningOnKVM()) return; - cpuid(KVM_CPUID_SIGNATURE + 0x01, &eax, &ebx, &ecx, &edx); + cpuid(kvm_cpuid_base + 0x01, &eax, &ebx, &ecx, &edx); if (eax & (1 << KVM_FEATURE_CLOCKSOURCE2)) msr = MSR_KVM_SYSTEM_TIME_NEW; else if (eax & (1 << KVM_FEATURE_CLOCKSOURCE))
diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c index fba4e52db684..c880cb10a1bc 100644 --- a/src/fw/paravirt.c +++ b/src/fw/paravirt.c @@ -56,20 +56,31 @@ inline int qemu_cfg_dma_enabled(void) static void kvm_detect(void) { + unsigned int i, kvmbase = 0, max = 0; unsigned int eax, ebx, ecx, edx; char signature[13]; - cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx); - memcpy(signature + 0, &ebx, 4); - memcpy(signature + 4, &ecx, 4); - memcpy(signature + 8, &edx, 4); - signature[12] = 0; + for (i = KVM_CPUID_SIGNATURE;; i += 0x100) { + eax = 0; + cpuid(i, &eax, &ebx, &ecx, &edx); + if (eax < i) + break; + memcpy(signature + 0, &ebx, 4); + memcpy(signature + 4, &ecx, 4); + memcpy(signature + 8, &edx, 4); + signature[12] = 0; + dprintf(1, "cpuid 0x%x: eax %x, signature '%s'\n", i, eax, signature); + if (strcmp(signature, "KVMKVMKVM") == 0) { + kvmbase = i; + max = eax; + } + } - if (strcmp(signature, "KVMKVMKVM") == 0) { + if (kvmbase) { dprintf(1, "Running on KVM\n"); PlatformRunningOn |= PF_KVM; - if (eax >= KVM_CPUID_SIGNATURE + 0x10) { - cpuid(KVM_CPUID_SIGNATURE + 0x10, &eax, &ebx, &ecx, &edx); + if (max >= kvmbase + 0x10) { + cpuid(kvmbase + 0x10, &eax, &ebx, &ecx, &edx); dprintf(1, "kvm: have invtsc, freq %u kHz\n", eax); tsctimer_setfreq(eax, "invtsc"); }
In case kvm emulates features of another hypervisor (for example hyperv) two VMM CPUID blocks will be present, one for the emulated hypervisor and one for kvm itself. This patch makes seabios loop over the VMM CPUID blocks to make sure it will properly detect kvm when multiple blocks are present. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> --- src/fw/paravirt.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-)