On Tue, 15 Feb 2022 16:08:16 +0100
Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
> On 2/15/22 13:06, Claudio Imbrenda wrote:
> > On Tue, 15 Feb 2022 11:46:32 +0100
> > Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
> >
> >> Several tests are in need of a way to check on which hypervisor
> >> and virtualization level they are running on to be able to fence
> >> certain tests. This patch adds functions that return true if a
> >> vm is running under KVM, LPAR or generally as a level 2 guest.
> >>
> >> To check if we're running under KVM we use the STSI 3.2.2
> >> instruction, let's define it's response structure in a central
> >> header.
> >>
> >
> > sorry, I had replied to the old series, let me reply here too
> >
> >
> > I think it would look cleaner if there was only one
> > "detect_environment" function, that would call stsi once and detect the
> > environment, then the various vm_is_* would become something like
> >
> > bool vm_is_*(void)
> > {
> > return detect_environment() == VM_IS_*;
> > }
> >
> > of course detect_environment would also cache the result with static
> > variables.
> >
> > bonus, we could make that function public, so a testcase could just
> > switch over the type of hypervisor it's being run on, instead of having
> > to use a series of ifs.
> >
> > and then maybe the various vm_is_* could become static inlines to be put
> > in the header.
> >
> > please note that "detect_environment" is just the first thing that came
> > to my mind, I have no preference regarding the name.
>
> I'd like to keep this patch as simple as possible because there are
> multiple patch sets which are gated by it.
>
> The vm.h code and the skey.c z/VM 6 check is a thorn in my side anyway
> and I'd rather have it fixed properly which will likely result in a lot
> of opinions being voiced.
>
> So I'd propose to rename vm_is_vm() to vm_is_guest2() and pick this patch.
ok for me
I'll rename the function and queue the patch
>
> >
> >> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> >> ---
> >> lib/s390x/stsi.h | 32 ++++++++++++++++++++++++++++
> >> lib/s390x/vm.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++--
> >> lib/s390x/vm.h | 3 +++
> >> s390x/stsi.c | 23 ++------------------
> >> 4 files changed, 90 insertions(+), 23 deletions(-)
> >> create mode 100644 lib/s390x/stsi.h
> >>
> >> diff --git a/lib/s390x/stsi.h b/lib/s390x/stsi.h
> >> new file mode 100644
> >> index 00000000..bebc492d
> >> --- /dev/null
> >> +++ b/lib/s390x/stsi.h
> >> @@ -0,0 +1,32 @@
> >> +/* SPDX-License-Identifier: GPL-2.0-only */
> >> +/*
> >> + * Structures used to Store System Information
> >> + *
> >> + * Copyright IBM Corp. 2022
> >> + */
> >> +
> >> +#ifndef _S390X_STSI_H_
> >> +#define _S390X_STSI_H_
> >> +
> >> +struct sysinfo_3_2_2 {
> >> + uint8_t reserved[31];
> >> + uint8_t count;
> >> + struct {
> >> + uint8_t reserved2[4];
> >> + uint16_t total_cpus;
> >> + uint16_t conf_cpus;
> >> + uint16_t standby_cpus;
> >> + uint16_t reserved_cpus;
> >> + uint8_t name[8];
> >> + uint32_t caf;
> >> + uint8_t cpi[16];
> >> + uint8_t reserved5[3];
> >> + uint8_t ext_name_encoding;
> >> + uint32_t reserved3;
> >> + uint8_t uuid[16];
> >> + } vm[8];
> >> + uint8_t reserved4[1504];
> >> + uint8_t ext_names[8][256];
> >> +};
> >> +
> >> +#endif /* _S390X_STSI_H_ */
> >> diff --git a/lib/s390x/vm.c b/lib/s390x/vm.c
> >> index a5b92863..91acd05b 100644
> >> --- a/lib/s390x/vm.c
> >> +++ b/lib/s390x/vm.c
> >> @@ -12,6 +12,7 @@
> >> #include <alloc_page.h>
> >> #include <asm/arch_def.h>
> >> #include "vm.h"
> >> +#include "stsi.h"
> >>
> >> /**
> >> * Detect whether we are running with TCG (instead of KVM)
> >> @@ -26,9 +27,13 @@ bool vm_is_tcg(void)
> >> if (initialized)
> >> return is_tcg;
> >>
> >> + if (!vm_is_vm()) {
> >> + initialized = true;
> >> + return is_tcg;
> >> + }
> >> +
> >> buf = alloc_page();
> >> - if (!buf)
> >> - return false;
> >> + assert(buf);
> >>
> >> if (stsi(buf, 1, 1, 1))
> >> goto out;
> >> @@ -43,3 +48,49 @@ out:
> >> free_page(buf);
> >> return is_tcg;
> >> }
> >> +
> >> +/**
> >> + * Detect whether we are running with KVM
> >> + */
> >> +bool vm_is_kvm(void)
> >> +{
> >> + /* EBCDIC for "KVM/" */
> >> + const uint8_t kvm_ebcdic[] = { 0xd2, 0xe5, 0xd4, 0x61 };
> >> + static bool initialized;
> >> + static bool is_kvm;
> >> + struct sysinfo_3_2_2 *stsi_322;
> >> +
> >> + if (initialized)
> >> + return is_kvm;
> >> +
> >> + if (!vm_is_vm() || vm_is_tcg()) {
> >> + initialized = true;
> >> + return is_kvm;
> >> + }
> >> +
> >> + stsi_322 = alloc_page();
> >> + assert(stsi_322);
> >> +
> >> + if (stsi(stsi_322, 3, 2, 2))
> >> + goto out;
> >> +
> >> + /*
> >> + * If the manufacturer string is "KVM/" in EBCDIC, then we
> >> + * are on KVM.
> >> + */
> >> + is_kvm = !memcmp(&stsi_322->vm[0].cpi, kvm_ebcdic, sizeof(kvm_ebcdic));
> >> + initialized = true;
> >> +out:
> >> + free_page(stsi_322);
> >> + return is_kvm;
> >> +}
> >> +
> >> +bool vm_is_lpar(void)
> >> +{
> >> + return stsi_get_fc() == 2;
> >> +}
> >> +
> >> +bool vm_is_vm(void)
> >> +{
> >> + return stsi_get_fc() == 3;
> >> +}
> >> diff --git a/lib/s390x/vm.h b/lib/s390x/vm.h
> >> index 7abba0cc..3aaf76af 100644
> >> --- a/lib/s390x/vm.h
> >> +++ b/lib/s390x/vm.h
> >> @@ -9,5 +9,8 @@
> >> #define _S390X_VM_H_
> >>
> >> bool vm_is_tcg(void);
> >> +bool vm_is_kvm(void);
> >> +bool vm_is_vm(void);
> >> +bool vm_is_lpar(void);
> >>
> >> #endif /* _S390X_VM_H_ */
> >> diff --git a/s390x/stsi.c b/s390x/stsi.c
> >> index 391f8849..dccc53e7 100644
> >> --- a/s390x/stsi.c
> >> +++ b/s390x/stsi.c
> >> @@ -13,27 +13,8 @@
> >> #include <asm/asm-offsets.h>
> >> #include <asm/interrupt.h>
> >> #include <smp.h>
> >> +#include <stsi.h>
> >>
> >> -struct stsi_322 {
> >> - uint8_t reserved[31];
> >> - uint8_t count;
> >> - struct {
> >> - uint8_t reserved2[4];
> >> - uint16_t total_cpus;
> >> - uint16_t conf_cpus;
> >> - uint16_t standby_cpus;
> >> - uint16_t reserved_cpus;
> >> - uint8_t name[8];
> >> - uint32_t caf;
> >> - uint8_t cpi[16];
> >> - uint8_t reserved5[3];
> >> - uint8_t ext_name_encoding;
> >> - uint32_t reserved3;
> >> - uint8_t uuid[16];
> >> - } vm[8];
> >> - uint8_t reserved4[1504];
> >> - uint8_t ext_names[8][256];
> >> -};
> >> static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));
> >>
> >> static void test_specs(void)
> >> @@ -91,7 +72,7 @@ static void test_3_2_2(void)
> >> /* EBCDIC for "KVM/" */
> >> const uint8_t cpi_kvm[] = { 0xd2, 0xe5, 0xd4, 0x61 };
> >> const char vm_name_ext[] = "kvm-unit-test";
> >> - struct stsi_322 *data = (void *)pagebuf;
> >> + struct sysinfo_3_2_2 *data = (void *)pagebuf;
> >>
> >> report_prefix_push("3.2.2");
> >>
> >
>
