* [kvm-unit-tests PATCH v2] x86/asyncpf: fix async page fault issues
@ 2023-12-18 7:14 Dan Wu
2023-12-25 1:51 ` Xiaoyao Li
0 siblings, 1 reply; 3+ messages in thread
From: Dan Wu @ 2023-12-18 7:14 UTC (permalink / raw)
To: seanjc, pbonzini, kvm; +Cc: xiaoyao.li, dan1.wu
KVM switched to use interrupt for 'page ready' APF event since Linux v5.10 and
the legacy mechanism using #PF was deprecated. Interrupt-based 'page-ready'
notification required KVM_ASYNC_PF_DELIVERY_AS_INT to be set as well in
MSR_KVM_ASYNC_PF_EN to enable asyncpf.
This patch tries to update asyncpf.c for the new interrupt-based notification.
It checks (KVM_FEATURE_ASYNC_PF && KVM_FEATURE_ASYNC_PF_INT) and implements
interrupt-based 'page-ready' handler.
To run this test, add the QEMU option "-cpu host" to check CPUID, since
KVM_FEATURE_ASYNC_PF_INT can't be detected without "-cpu host".
Update the usage of how to setup cgroup for different cgroup versions.
Signed-off-by: Dan Wu <dan1.wu@intel.com>
---
The test is based on asyncpf.c and simplifies implementation by reducing the memory
access round from 2 to 1.
v2:
- removed asyncpf_int.c and asyncpf.h and modified asyncpf.c to use ASYNC_PF_INT.
---
lib/x86/processor.h | 6 ++
x86/asyncpf.c | 152 +++++++++++++++++++++++++++-----------------
x86/unittests.cfg | 2 +-
3 files changed, 101 insertions(+), 59 deletions(-)
diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index 44f4fd1e..1a0f1243 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -263,6 +263,12 @@ static inline bool is_intel(void)
#define X86_FEATURE_ARCH_CAPABILITIES (CPUID(0x7, 0, EDX, 29))
#define X86_FEATURE_PKS (CPUID(0x7, 0, ECX, 31))
+/*
+ * KVM defined leafs
+ */
+#define KVM_FEATURE_ASYNC_PF (CPUID(0x40000001, 0, EAX, 4))
+#define KVM_FEATURE_ASYNC_PF_INT (CPUID(0x40000001, 0, EAX, 14))
+
/*
* Extended Leafs, a.k.a. AMD defined
*/
diff --git a/x86/asyncpf.c b/x86/asyncpf.c
index bc515be9..8ae9ea40 100644
--- a/x86/asyncpf.c
+++ b/x86/asyncpf.c
@@ -1,111 +1,147 @@
/*
* Async PF test. For the test to actually do anything it needs to be started
- * in memory cgroup with 512M of memory and with more then 1G memory provided
+ * in memory cgroup with 512M of memory and with more than 1G memory provided
* to the guest.
*
+ * To identify the cgroup version on Linux:
+ * stat -fc %T /sys/fs/cgroup/
+ *
+ * If the output is tmpfs, your system is using cgroup v1:
* To create cgroup do as root:
* mkdir /dev/cgroup
* mount -t cgroup none -omemory /dev/cgroup
* chmod a+rxw /dev/cgroup/
- *
* From a shell you will start qemu from:
* mkdir /dev/cgroup/1
* echo $$ > /dev/cgroup/1/tasks
* echo 512M > /dev/cgroup/1/memory.limit_in_bytes
*
+ * If the output is cgroup2fs, your system is using cgroup v2:
+ * mkdir /sys/fs/cgroup/cg1
+ * echo $$ > /sys/fs/cgroup/cg1/cgroup.procs
+ * echo 512M > /sys/fs/cgroup/cg1/memory.max
+ *
*/
-#include "x86/msr.h"
#include "x86/processor.h"
-#include "x86/apic-defs.h"
#include "x86/apic.h"
-#include "x86/desc.h"
#include "x86/isr.h"
#include "x86/vm.h"
-
-#include "asm/page.h"
#include "alloc.h"
-#include "libcflat.h"
#include "vmalloc.h"
-#include <stdint.h>
#define KVM_PV_REASON_PAGE_NOT_PRESENT 1
-#define KVM_PV_REASON_PAGE_READY 2
#define MSR_KVM_ASYNC_PF_EN 0x4b564d02
+#define MSR_KVM_ASYNC_PF_INT 0x4b564d06
+#define MSR_KVM_ASYNC_PF_ACK 0x4b564d07
#define KVM_ASYNC_PF_ENABLED (1 << 0)
#define KVM_ASYNC_PF_SEND_ALWAYS (1 << 1)
+#define KVM_ASYNC_PF_DELIVERY_AS_INT (1 << 3)
+
+#define HYPERVISOR_CALLBACK_VECTOR 0xf3
+
+struct kvm_vcpu_pv_apf_data {
+ /* Used for 'page not present' events delivered via #PF */
+ uint32_t flags;
+
+ /* Used for 'page ready' events delivered via interrupt notification */
+ uint32_t token;
+
+ uint8_t pad[56];
+ uint32_t enabled;
+} apf_reason __attribute__((aligned(64)));
-volatile uint32_t apf_reason __attribute__((aligned(64)));
char *buf;
+void* virt;
volatile uint64_t i;
volatile uint64_t phys;
+volatile uint32_t saved_token;
+volatile uint32_t asyncpf_num;
-static inline uint32_t get_apf_reason(void)
+static inline uint32_t get_and_clear_apf_reason(void)
{
- uint32_t r = apf_reason;
- apf_reason = 0;
+ uint32_t r = apf_reason.flags;
+ apf_reason.flags = 0;
return r;
}
-static void pf_isr(struct ex_regs *r)
+static void handle_interrupt(isr_regs_t *regs)
{
- void* virt = (void*)((ulong)(buf+i) & ~(PAGE_SIZE-1));
- uint32_t reason = get_apf_reason();
+ uint32_t apf_token = apf_reason.token;
+
+ apf_reason.token = 0;
+ wrmsr(MSR_KVM_ASYNC_PF_ACK, 1);
+
+ if (apf_token == 0xffffffff) {
+ report_pass("Wakeup all, got token 0x%x", apf_token);
+ } else if (apf_token == saved_token) {
+ asyncpf_num++;
+ install_pte(phys_to_virt(read_cr3()), 1, virt, phys | PT_PRESENT_MASK | PT_WRITABLE_MASK, 0);
+ phys = 0;
+ } else {
+ report_fail("unexpected async pf int token 0x%x", apf_token);
+ }
+
+ eoi();
+}
+static void handle_pf(struct ex_regs *r)
+{
+ virt = (void*)((ulong)(buf+i) & ~(PAGE_SIZE-1));
+ uint32_t reason = get_and_clear_apf_reason();
switch (reason) {
- case 0:
- report_fail("unexpected #PF at %#lx", read_cr2());
- break;
- case KVM_PV_REASON_PAGE_NOT_PRESENT:
- phys = virt_to_pte_phys(phys_to_virt(read_cr3()), virt);
- install_pte(phys_to_virt(read_cr3()), 1, virt, phys, 0);
- write_cr3(read_cr3());
- report_pass("Got not present #PF token %lx virt addr %p phys addr %#" PRIx64,
- read_cr2(), virt, phys);
- while(phys) {
- safe_halt(); /* enables irq */
- cli();
- }
- break;
- case KVM_PV_REASON_PAGE_READY:
- report_pass("Got present #PF token %lx", read_cr2());
- if ((uint32_t)read_cr2() == ~0)
- break;
- install_pte(phys_to_virt(read_cr3()), 1, virt, phys | PT_PRESENT_MASK | PT_WRITABLE_MASK, 0);
- write_cr3(read_cr3());
- phys = 0;
- break;
- default:
- report_fail("unexpected async pf reason %" PRId32, reason);
- break;
+ case 0:
+ report_fail("unexpected #PF at %#lx", read_cr2());
+ exit(report_summary());
+ case KVM_PV_REASON_PAGE_NOT_PRESENT:
+ phys = virt_to_pte_phys(phys_to_virt(read_cr3()), virt);
+ install_pte(phys_to_virt(read_cr3()), 1, virt, phys, 0);
+ write_cr3(read_cr3());
+ saved_token = read_cr2();
+ while (phys) {
+ safe_halt(); /* enables irq */
+ }
+ break;
+ default:
+ report_fail("unexpected async pf with reason 0x%x", reason);
+ exit(report_summary());
}
}
-#define MEM 1ull*1024*1024*1024
+#define MEM (1ull*1024*1024*1024)
int main(int ac, char **av)
{
- int loop = 2;
+ if (!this_cpu_has(KVM_FEATURE_ASYNC_PF)) {
+ report_skip("KVM_FEATURE_ASYNC_PF is not supported\n");
+ return report_summary();
+ }
+
+ if (!this_cpu_has(KVM_FEATURE_ASYNC_PF_INT)) {
+ report_skip("KVM_FEATURE_ASYNC_PF_INT is not supported\n");
+ return report_summary();
+ }
setup_vm();
- printf("install handler\n");
- handle_exception(14, pf_isr);
- apf_reason = 0;
- printf("enable async pf\n");
+
+ handle_exception(PF_VECTOR, handle_pf);
+ handle_irq(HYPERVISOR_CALLBACK_VECTOR, handle_interrupt);
+ memset(&apf_reason, 0, sizeof(apf_reason));
+
+ wrmsr(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);
wrmsr(MSR_KVM_ASYNC_PF_EN, virt_to_phys((void*)&apf_reason) |
- KVM_ASYNC_PF_SEND_ALWAYS | KVM_ASYNC_PF_ENABLED);
- printf("alloc memory\n");
+ KVM_ASYNC_PF_SEND_ALWAYS | KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT);
+
buf = malloc(MEM);
sti();
- while(loop--) {
- printf("start loop\n");
- /* access a lot of memory to make host swap it out */
- for (i=0; i < MEM; i+=4096)
- buf[i] = 1;
- printf("end loop\n");
- }
- cli();
+ /* access a lot of memory to make host swap it out */
+ for (i = 0; i < MEM; i += 4096)
+ buf[i] = 1;
+
+ cli();
+ report(asyncpf_num > 0, "get %d async pf events ('page not present' #PF event with matched "
+ "'page ready' interrupt event )", asyncpf_num);
return report_summary();
}
diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index 3fe59449..e3d051bc 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -172,7 +172,7 @@ extra_params = -cpu max
[asyncpf]
file = asyncpf.flat
-extra_params = -m 2048
+extra_params = -cpu host -m 2048
[emulator]
file = emulator.flat
--
2.39.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [kvm-unit-tests PATCH v2] x86/asyncpf: fix async page fault issues
2023-12-18 7:14 [kvm-unit-tests PATCH v2] x86/asyncpf: fix async page fault issues Dan Wu
@ 2023-12-25 1:51 ` Xiaoyao Li
2023-12-26 5:15 ` Wu, Dan1
0 siblings, 1 reply; 3+ messages in thread
From: Xiaoyao Li @ 2023-12-25 1:51 UTC (permalink / raw)
To: Dan Wu, seanjc, pbonzini, kvm
On 12/18/2023 3:14 PM, Dan Wu wrote:
> KVM switched to use interrupt for 'page ready' APF event since Linux v5.10 and
> the legacy mechanism using #PF was deprecated. Interrupt-based 'page-ready'
> notification required KVM_ASYNC_PF_DELIVERY_AS_INT to be set as well in
> MSR_KVM_ASYNC_PF_EN to enable asyncpf.
>
> This patch tries to update asyncpf.c for the new interrupt-based notification.
please avoid using 'This patch', and just use imperative mood.
> It checks (KVM_FEATURE_ASYNC_PF && KVM_FEATURE_ASYNC_PF_INT) and implements
> interrupt-based 'page-ready' handler.
>
> To run this test, add the QEMU option "-cpu host" to check CPUID, since
> KVM_FEATURE_ASYNC_PF_INT can't be detected without "-cpu host".
>
> Update the usage of how to setup cgroup for different cgroup versions.
>
> Signed-off-by: Dan Wu <dan1.wu@intel.com>
This patch looks good to me, apart from some nits above and below.
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
> ---
> The test is based on asyncpf.c and simplifies implementation by reducing the memory
> access round from 2 to 1.
>
> v2:
> - removed asyncpf_int.c and asyncpf.h and modified asyncpf.c to use ASYNC_PF_INT.
> ---
> lib/x86/processor.h | 6 ++
> x86/asyncpf.c | 152 +++++++++++++++++++++++++++-----------------
> x86/unittests.cfg | 2 +-
> 3 files changed, 101 insertions(+), 59 deletions(-)
>
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index 44f4fd1e..1a0f1243 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -263,6 +263,12 @@ static inline bool is_intel(void)
> #define X86_FEATURE_ARCH_CAPABILITIES (CPUID(0x7, 0, EDX, 29))
> #define X86_FEATURE_PKS (CPUID(0x7, 0, ECX, 31))
>
> +/*
> + * KVM defined leafs
> + */
> +#define KVM_FEATURE_ASYNC_PF (CPUID(0x40000001, 0, EAX, 4))
> +#define KVM_FEATURE_ASYNC_PF_INT (CPUID(0x40000001, 0, EAX, 14))
> +
> /*
> * Extended Leafs, a.k.a. AMD defined
> */
> diff --git a/x86/asyncpf.c b/x86/asyncpf.c
> index bc515be9..8ae9ea40 100644
> --- a/x86/asyncpf.c
> +++ b/x86/asyncpf.c
> @@ -1,111 +1,147 @@
> /*
> * Async PF test. For the test to actually do anything it needs to be started
> - * in memory cgroup with 512M of memory and with more then 1G memory provided
> + * in memory cgroup with 512M of memory and with more than 1G memory provided
> * to the guest.
> *
> + * To identify the cgroup version on Linux:
> + * stat -fc %T /sys/fs/cgroup/
> + *
> + * If the output is tmpfs, your system is using cgroup v1:
> * To create cgroup do as root:
> * mkdir /dev/cgroup
> * mount -t cgroup none -omemory /dev/cgroup
> * chmod a+rxw /dev/cgroup/
> - *
keep this line is better, IMO.
> * From a shell you will start qemu from:
> * mkdir /dev/cgroup/1
> * echo $$ > /dev/cgroup/1/tasks
> * echo 512M > /dev/cgroup/1/memory.limit_in_bytes
> *
> + * If the output is cgroup2fs, your system is using cgroup v2:
> + * mkdir /sys/fs/cgroup/cg1
> + * echo $$ > /sys/fs/cgroup/cg1/cgroup.procs
> + * echo 512M > /sys/fs/cgroup/cg1/memory.max
> + *
> */
> -#include "x86/msr.h"
> #include "x86/processor.h"
> -#include "x86/apic-defs.h"
> #include "x86/apic.h"
> -#include "x86/desc.h"
> #include "x86/isr.h"
> #include "x86/vm.h"
> -
> -#include "asm/page.h"
> #include "alloc.h"
> -#include "libcflat.h"
> #include "vmalloc.h"
> -#include <stdint.h>
maybe it deserves one line mentioning in the commit message, like
"cleaning up the include headers"
> #define KVM_PV_REASON_PAGE_NOT_PRESENT 1
> -#define KVM_PV_REASON_PAGE_READY 2
>
> #define MSR_KVM_ASYNC_PF_EN 0x4b564d02
> +#define MSR_KVM_ASYNC_PF_INT 0x4b564d06
> +#define MSR_KVM_ASYNC_PF_ACK 0x4b564d07
>
> #define KVM_ASYNC_PF_ENABLED (1 << 0)
> #define KVM_ASYNC_PF_SEND_ALWAYS (1 << 1)
> +#define KVM_ASYNC_PF_DELIVERY_AS_INT (1 << 3)
> +
> +#define HYPERVISOR_CALLBACK_VECTOR 0xf3
> +
> +struct kvm_vcpu_pv_apf_data {
> + /* Used for 'page not present' events delivered via #PF */
> + uint32_t flags;
> +
> + /* Used for 'page ready' events delivered via interrupt notification */
> + uint32_t token;
> +
> + uint8_t pad[56];
> + uint32_t enabled;
> +} apf_reason __attribute__((aligned(64)));
as well, it deserves some words in commit message.
> -volatile uint32_t apf_reason __attribute__((aligned(64)));
> char *buf;
> +void* virt;
> volatile uint64_t i;
> volatile uint64_t phys;
> +volatile uint32_t saved_token;
> +volatile uint32_t asyncpf_num;
>
> -static inline uint32_t get_apf_reason(void)
> +static inline uint32_t get_and_clear_apf_reason(void)
> {
> - uint32_t r = apf_reason;
> - apf_reason = 0;
> + uint32_t r = apf_reason.flags;
> + apf_reason.flags = 0;
> return r;
> }
>
> -static void pf_isr(struct ex_regs *r)
> +static void handle_interrupt(isr_regs_t *regs)
> {
> - void* virt = (void*)((ulong)(buf+i) & ~(PAGE_SIZE-1));
> - uint32_t reason = get_apf_reason();
> + uint32_t apf_token = apf_reason.token;
> +
> + apf_reason.token = 0;
> + wrmsr(MSR_KVM_ASYNC_PF_ACK, 1);
> +
> + if (apf_token == 0xffffffff) {
> + report_pass("Wakeup all, got token 0x%x", apf_token);
> + } else if (apf_token == saved_token) {
> + asyncpf_num++;
> + install_pte(phys_to_virt(read_cr3()), 1, virt, phys | PT_PRESENT_MASK | PT_WRITABLE_MASK, 0);
> + phys = 0;
> + } else {
> + report_fail("unexpected async pf int token 0x%x", apf_token);
> + }
> +
> + eoi();
> +}
>
> +static void handle_pf(struct ex_regs *r)
> +{
> + virt = (void*)((ulong)(buf+i) & ~(PAGE_SIZE-1));
> + uint32_t reason = get_and_clear_apf_reason();
> switch (reason) {
> - case 0:
> - report_fail("unexpected #PF at %#lx", read_cr2());
> - break;
> - case KVM_PV_REASON_PAGE_NOT_PRESENT:
> - phys = virt_to_pte_phys(phys_to_virt(read_cr3()), virt);
> - install_pte(phys_to_virt(read_cr3()), 1, virt, phys, 0);
> - write_cr3(read_cr3());
> - report_pass("Got not present #PF token %lx virt addr %p phys addr %#" PRIx64,
> - read_cr2(), virt, phys);
> - while(phys) {
> - safe_halt(); /* enables irq */
> - cli();
> - }
> - break;
> - case KVM_PV_REASON_PAGE_READY:
> - report_pass("Got present #PF token %lx", read_cr2());
> - if ((uint32_t)read_cr2() == ~0)
> - break;
> - install_pte(phys_to_virt(read_cr3()), 1, virt, phys | PT_PRESENT_MASK | PT_WRITABLE_MASK, 0);
> - write_cr3(read_cr3());
> - phys = 0;
> - break;
> - default:
> - report_fail("unexpected async pf reason %" PRId32, reason);
> - break;
> + case 0:
> + report_fail("unexpected #PF at %#lx", read_cr2());
> + exit(report_summary());
> + case KVM_PV_REASON_PAGE_NOT_PRESENT:
> + phys = virt_to_pte_phys(phys_to_virt(read_cr3()), virt);
> + install_pte(phys_to_virt(read_cr3()), 1, virt, phys, 0);
> + write_cr3(read_cr3());
> + saved_token = read_cr2();
> + while (phys) {
> + safe_halt(); /* enables irq */
> + }
> + break;
> + default:
> + report_fail("unexpected async pf with reason 0x%x", reason);
> + exit(report_summary());
> }
> }
>
> -#define MEM 1ull*1024*1024*1024
> +#define MEM (1ull*1024*1024*1024)
>
> int main(int ac, char **av)
> {
> - int loop = 2;
> + if (!this_cpu_has(KVM_FEATURE_ASYNC_PF)) {
> + report_skip("KVM_FEATURE_ASYNC_PF is not supported\n");
> + return report_summary();
> + }
> +
> + if (!this_cpu_has(KVM_FEATURE_ASYNC_PF_INT)) {
> + report_skip("KVM_FEATURE_ASYNC_PF_INT is not supported\n");
> + return report_summary();
> + }
>
> setup_vm();
> - printf("install handler\n");
> - handle_exception(14, pf_isr);
> - apf_reason = 0;
> - printf("enable async pf\n");
> +
> + handle_exception(PF_VECTOR, handle_pf);
> + handle_irq(HYPERVISOR_CALLBACK_VECTOR, handle_interrupt);
> + memset(&apf_reason, 0, sizeof(apf_reason));
> +
> + wrmsr(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);
> wrmsr(MSR_KVM_ASYNC_PF_EN, virt_to_phys((void*)&apf_reason) |
> - KVM_ASYNC_PF_SEND_ALWAYS | KVM_ASYNC_PF_ENABLED);
> - printf("alloc memory\n");
> + KVM_ASYNC_PF_SEND_ALWAYS | KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT);
> +
> buf = malloc(MEM);
> sti();
> - while(loop--) {
> - printf("start loop\n");
> - /* access a lot of memory to make host swap it out */
> - for (i=0; i < MEM; i+=4096)
> - buf[i] = 1;
> - printf("end loop\n");
> - }
> - cli();
>
> + /* access a lot of memory to make host swap it out */
> + for (i = 0; i < MEM; i += 4096)
> + buf[i] = 1;
> +
> + cli();
> + report(asyncpf_num > 0, "get %d async pf events ('page not present' #PF event with matched "
> + "'page ready' interrupt event )", asyncpf_num);
> return report_summary();
> }
> diff --git a/x86/unittests.cfg b/x86/unittests.cfg
> index 3fe59449..e3d051bc 100644
> --- a/x86/unittests.cfg
> +++ b/x86/unittests.cfg
> @@ -172,7 +172,7 @@ extra_params = -cpu max
>
> [asyncpf]
> file = asyncpf.flat
> -extra_params = -m 2048
> +extra_params = -cpu host -m 2048
>
> [emulator]
> file = emulator.flat
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [kvm-unit-tests PATCH v2] x86/asyncpf: fix async page fault issues
2023-12-25 1:51 ` Xiaoyao Li
@ 2023-12-26 5:15 ` Wu, Dan1
0 siblings, 0 replies; 3+ messages in thread
From: Wu, Dan1 @ 2023-12-26 5:15 UTC (permalink / raw)
To: Xiaoyao Li, seanjc, pbonzini, kvm
On 12/25/2023 9:51 AM, Xiaoyao Li wrote:
> On 12/18/2023 3:14 PM, Dan Wu wrote:
>> KVM switched to use interrupt for 'page ready' APF event since Linux
>> v5.10 and
>> the legacy mechanism using #PF was deprecated. Interrupt-based
>> 'page-ready'
>> notification required KVM_ASYNC_PF_DELIVERY_AS_INT to be set as well in
>> MSR_KVM_ASYNC_PF_EN to enable asyncpf.
>>
>> This patch tries to update asyncpf.c for the new interrupt-based
>> notification.
>
> please avoid using 'This patch', and just use imperative mood.
thanks for your suggestion.
>
>> It checks (KVM_FEATURE_ASYNC_PF && KVM_FEATURE_ASYNC_PF_INT) and
>> implements
>> interrupt-based 'page-ready' handler.
>>
>> To run this test, add the QEMU option "-cpu host" to check CPUID, since
>> KVM_FEATURE_ASYNC_PF_INT can't be detected without "-cpu host".
>>
>> Update the usage of how to setup cgroup for different cgroup versions.
>>
>> Signed-off-by: Dan Wu <dan1.wu@intel.com>
>
> This patch looks good to me, apart from some nits above and below.
OK, I will modify them in the next version. Thanks for your review.
>
> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
>
>> ---
>> The test is based on asyncpf.c and simplifies implementation by
>> reducing the memory
>> access round from 2 to 1.
>>
>> v2:
>> - removed asyncpf_int.c and asyncpf.h and modified asyncpf.c to use
>> ASYNC_PF_INT.
>> ---
>> lib/x86/processor.h | 6 ++
>> x86/asyncpf.c | 152 +++++++++++++++++++++++++++-----------------
>> x86/unittests.cfg | 2 +-
>> 3 files changed, 101 insertions(+), 59 deletions(-)
>>
>> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
>> index 44f4fd1e..1a0f1243 100644
>> --- a/lib/x86/processor.h
>> +++ b/lib/x86/processor.h
>> @@ -263,6 +263,12 @@ static inline bool is_intel(void)
>> #define X86_FEATURE_ARCH_CAPABILITIES (CPUID(0x7, 0, EDX, 29))
>> #define X86_FEATURE_PKS (CPUID(0x7, 0, ECX, 31))
>> +/*
>> + * KVM defined leafs
>> + */
>> +#define KVM_FEATURE_ASYNC_PF (CPUID(0x40000001, 0, EAX, 4))
>> +#define KVM_FEATURE_ASYNC_PF_INT (CPUID(0x40000001, 0, EAX, 14))
>> +
>> /*
>> * Extended Leafs, a.k.a. AMD defined
>> */
>> diff --git a/x86/asyncpf.c b/x86/asyncpf.c
>> index bc515be9..8ae9ea40 100644
>> --- a/x86/asyncpf.c
>> +++ b/x86/asyncpf.c
>> @@ -1,111 +1,147 @@
>> /*
>> * Async PF test. For the test to actually do anything it needs to
>> be started
>> - * in memory cgroup with 512M of memory and with more then 1G memory
>> provided
>> + * in memory cgroup with 512M of memory and with more than 1G memory
>> provided
>> * to the guest.
>> *
>> + * To identify the cgroup version on Linux:
>> + * stat -fc %T /sys/fs/cgroup/
>> + *
>> + * If the output is tmpfs, your system is using cgroup v1:
>> * To create cgroup do as root:
>> * mkdir /dev/cgroup
>> * mount -t cgroup none -omemory /dev/cgroup
>> * chmod a+rxw /dev/cgroup/
>> - *
>
> keep this line is better, IMO.
>
>> * From a shell you will start qemu from:
>> * mkdir /dev/cgroup/1
>> * echo $$ > /dev/cgroup/1/tasks
>> * echo 512M > /dev/cgroup/1/memory.limit_in_bytes
>> *
>> + * If the output is cgroup2fs, your system is using cgroup v2:
>> + * mkdir /sys/fs/cgroup/cg1
>> + * echo $$ > /sys/fs/cgroup/cg1/cgroup.procs
>> + * echo 512M > /sys/fs/cgroup/cg1/memory.max
>> + *
>> */
>> -#include "x86/msr.h"
>> #include "x86/processor.h"
>> -#include "x86/apic-defs.h"
>> #include "x86/apic.h"
>> -#include "x86/desc.h"
>> #include "x86/isr.h"
>> #include "x86/vm.h"
>> -
>> -#include "asm/page.h"
>> #include "alloc.h"
>> -#include "libcflat.h"
>> #include "vmalloc.h"
>> -#include <stdint.h>
>
> maybe it deserves one line mentioning in the commit message, like
> "cleaning up the include headers"
>
>> #define KVM_PV_REASON_PAGE_NOT_PRESENT 1
>> -#define KVM_PV_REASON_PAGE_READY 2
>> #define MSR_KVM_ASYNC_PF_EN 0x4b564d02
>> +#define MSR_KVM_ASYNC_PF_INT 0x4b564d06
>> +#define MSR_KVM_ASYNC_PF_ACK 0x4b564d07
>> #define KVM_ASYNC_PF_ENABLED (1 << 0)
>> #define KVM_ASYNC_PF_SEND_ALWAYS (1 << 1)
>> +#define KVM_ASYNC_PF_DELIVERY_AS_INT (1 << 3)
>> +
>> +#define HYPERVISOR_CALLBACK_VECTOR 0xf3
>> +
>> +struct kvm_vcpu_pv_apf_data {
>> + /* Used for 'page not present' events delivered via #PF */
>> + uint32_t flags;
>> +
>> + /* Used for 'page ready' events delivered via interrupt
>> notification */
>> + uint32_t token;
>> +
>> + uint8_t pad[56];
>> + uint32_t enabled;
>> +} apf_reason __attribute__((aligned(64)));
>
> as well, it deserves some words in commit message.
>
>> -volatile uint32_t apf_reason __attribute__((aligned(64)));
>> char *buf;
>> +void* virt;
>> volatile uint64_t i;
>> volatile uint64_t phys;
>> +volatile uint32_t saved_token;
>> +volatile uint32_t asyncpf_num;
>> -static inline uint32_t get_apf_reason(void)
>> +static inline uint32_t get_and_clear_apf_reason(void)
>> {
>> - uint32_t r = apf_reason;
>> - apf_reason = 0;
>> + uint32_t r = apf_reason.flags;
>> + apf_reason.flags = 0;
>> return r;
>> }
>> -static void pf_isr(struct ex_regs *r)
>> +static void handle_interrupt(isr_regs_t *regs)
>> {
>> - void* virt = (void*)((ulong)(buf+i) & ~(PAGE_SIZE-1));
>> - uint32_t reason = get_apf_reason();
>> + uint32_t apf_token = apf_reason.token;
>> +
>> + apf_reason.token = 0;
>> + wrmsr(MSR_KVM_ASYNC_PF_ACK, 1);
>> +
>> + if (apf_token == 0xffffffff) {
>> + report_pass("Wakeup all, got token 0x%x", apf_token);
>> + } else if (apf_token == saved_token) {
>> + asyncpf_num++;
>> + install_pte(phys_to_virt(read_cr3()), 1, virt, phys |
>> PT_PRESENT_MASK | PT_WRITABLE_MASK, 0);
>> + phys = 0;
>> + } else {
>> + report_fail("unexpected async pf int token 0x%x", apf_token);
>> + }
>> +
>> + eoi();
>> +}
>> +static void handle_pf(struct ex_regs *r)
>> +{
>> + virt = (void*)((ulong)(buf+i) & ~(PAGE_SIZE-1));
>> + uint32_t reason = get_and_clear_apf_reason();
>> switch (reason) {
>> - case 0:
>> - report_fail("unexpected #PF at %#lx", read_cr2());
>> - break;
>> - case KVM_PV_REASON_PAGE_NOT_PRESENT:
>> - phys = virt_to_pte_phys(phys_to_virt(read_cr3()), virt);
>> - install_pte(phys_to_virt(read_cr3()), 1, virt, phys, 0);
>> - write_cr3(read_cr3());
>> - report_pass("Got not present #PF token %lx virt addr %p
>> phys addr %#" PRIx64,
>> - read_cr2(), virt, phys);
>> - while(phys) {
>> - safe_halt(); /* enables irq */
>> - cli();
>> - }
>> - break;
>> - case KVM_PV_REASON_PAGE_READY:
>> - report_pass("Got present #PF token %lx", read_cr2());
>> - if ((uint32_t)read_cr2() == ~0)
>> - break;
>> - install_pte(phys_to_virt(read_cr3()), 1, virt, phys |
>> PT_PRESENT_MASK | PT_WRITABLE_MASK, 0);
>> - write_cr3(read_cr3());
>> - phys = 0;
>> - break;
>> - default:
>> - report_fail("unexpected async pf reason %" PRId32, reason);
>> - break;
>> + case 0:
>> + report_fail("unexpected #PF at %#lx", read_cr2());
>> + exit(report_summary());
>> + case KVM_PV_REASON_PAGE_NOT_PRESENT:
>> + phys = virt_to_pte_phys(phys_to_virt(read_cr3()), virt);
>> + install_pte(phys_to_virt(read_cr3()), 1, virt, phys, 0);
>> + write_cr3(read_cr3());
>> + saved_token = read_cr2();
>> + while (phys) {
>> + safe_halt(); /* enables irq */
>> + }
>> + break;
>> + default:
>> + report_fail("unexpected async pf with reason 0x%x", reason);
>> + exit(report_summary());
>> }
>> }
>> -#define MEM 1ull*1024*1024*1024
>> +#define MEM (1ull*1024*1024*1024)
>> int main(int ac, char **av)
>> {
>> - int loop = 2;
>> + if (!this_cpu_has(KVM_FEATURE_ASYNC_PF)) {
>> + report_skip("KVM_FEATURE_ASYNC_PF is not supported\n");
>> + return report_summary();
>> + }
>> +
>> + if (!this_cpu_has(KVM_FEATURE_ASYNC_PF_INT)) {
>> + report_skip("KVM_FEATURE_ASYNC_PF_INT is not supported\n");
>> + return report_summary();
>> + }
>> setup_vm();
>> - printf("install handler\n");
>> - handle_exception(14, pf_isr);
>> - apf_reason = 0;
>> - printf("enable async pf\n");
>> +
>> + handle_exception(PF_VECTOR, handle_pf);
>> + handle_irq(HYPERVISOR_CALLBACK_VECTOR, handle_interrupt);
>> + memset(&apf_reason, 0, sizeof(apf_reason));
>> +
>> + wrmsr(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);
>> wrmsr(MSR_KVM_ASYNC_PF_EN, virt_to_phys((void*)&apf_reason) |
>> - KVM_ASYNC_PF_SEND_ALWAYS | KVM_ASYNC_PF_ENABLED);
>> - printf("alloc memory\n");
>> + KVM_ASYNC_PF_SEND_ALWAYS | KVM_ASYNC_PF_ENABLED |
>> KVM_ASYNC_PF_DELIVERY_AS_INT);
>> +
>> buf = malloc(MEM);
>> sti();
>> - while(loop--) {
>> - printf("start loop\n");
>> - /* access a lot of memory to make host swap it out */
>> - for (i=0; i < MEM; i+=4096)
>> - buf[i] = 1;
>> - printf("end loop\n");
>> - }
>> - cli();
>> + /* access a lot of memory to make host swap it out */
>> + for (i = 0; i < MEM; i += 4096)
>> + buf[i] = 1;
>> +
>> + cli();
>> + report(asyncpf_num > 0, "get %d async pf events ('page not
>> present' #PF event with matched "
>> + "'page ready' interrupt event )", asyncpf_num);
>> return report_summary();
>> }
>> diff --git a/x86/unittests.cfg b/x86/unittests.cfg
>> index 3fe59449..e3d051bc 100644
>> --- a/x86/unittests.cfg
>> +++ b/x86/unittests.cfg
>> @@ -172,7 +172,7 @@ extra_params = -cpu max
>> [asyncpf]
>> file = asyncpf.flat
>> -extra_params = -m 2048
>> +extra_params = -cpu host -m 2048
>> [emulator]
>> file = emulator.flat
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-12-26 5:15 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2023-12-18 7:14 [kvm-unit-tests PATCH v2] x86/asyncpf: fix async page fault issues Dan Wu
2023-12-25 1:51 ` Xiaoyao Li
2023-12-26 5:15 ` Wu, Dan1
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