* [kvm-unit-tests PATCH 1/3] x86: realmode: initialize idtr
2020-06-26 9:23 [kvm-unit-tests PATCH 0/3] x86: realmode: fixes Nadav Amit
@ 2020-06-26 9:23 ` Nadav Amit
2020-06-26 10:41 ` Paolo Bonzini
2020-06-26 9:23 ` [kvm-unit-tests PATCH 2/3] x86: realmode: hlt loop as fallback on exit Nadav Amit
` (2 subsequent siblings)
3 siblings, 1 reply; 6+ messages in thread
From: Nadav Amit @ 2020-06-26 9:23 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: kvm, Nadav Amit
The realmode test does not initialize the IDTR, assuming that its base
is zero and its limit 0x3ff. Initialize it, as the BIOS might not set it
as such.
Signed-off-by: Nadav Amit <namit@vmware.com>
---
x86/realmode.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/x86/realmode.c b/x86/realmode.c
index 234d607..ef79f7e 100644
--- a/x86/realmode.c
+++ b/x86/realmode.c
@@ -1799,6 +1799,7 @@ void realmode_start(void)
unsigned long long r_gdt[] = { 0, 0x9b000000ffff, 0x93000000ffff };
struct table_descr r_gdt_descr = { sizeof(r_gdt) - 1, &r_gdt };
+struct table_descr r_idt_descr = { 0x3ff, 0 };
asm(
".section .init \n\t"
@@ -1819,6 +1820,7 @@ asm(
".text \n\t"
"start: \n\t"
"lgdt r_gdt_descr \n\t"
+ "lidt r_idt_descr \n\t"
"ljmp $8, $1f; 1: \n\t"
".code16gcc \n\t"
"mov $16, %eax \n\t"
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [kvm-unit-tests PATCH 1/3] x86: realmode: initialize idtr
2020-06-26 9:23 ` [kvm-unit-tests PATCH 1/3] x86: realmode: initialize idtr Nadav Amit
@ 2020-06-26 10:41 ` Paolo Bonzini
0 siblings, 0 replies; 6+ messages in thread
From: Paolo Bonzini @ 2020-06-26 10:41 UTC (permalink / raw)
To: Nadav Amit; +Cc: kvm
On 26/06/20 11:23, Nadav Amit wrote:
> The realmode test does not initialize the IDTR, assuming that its base
> is zero and its limit 0x3ff. Initialize it, as the BIOS might not set it
> as such.
Rather the bootloader: realmode.flat is started as multiboot, that is in
a 32-bit protected mode environment---which includes an IDT.
Paolo
> Signed-off-by: Nadav Amit <namit@vmware.com>
> ---
> x86/realmode.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/x86/realmode.c b/x86/realmode.c
> index 234d607..ef79f7e 100644
> --- a/x86/realmode.c
> +++ b/x86/realmode.c
> @@ -1799,6 +1799,7 @@ void realmode_start(void)
> unsigned long long r_gdt[] = { 0, 0x9b000000ffff, 0x93000000ffff };
>
> struct table_descr r_gdt_descr = { sizeof(r_gdt) - 1, &r_gdt };
> +struct table_descr r_idt_descr = { 0x3ff, 0 };
>
> asm(
> ".section .init \n\t"
> @@ -1819,6 +1820,7 @@ asm(
> ".text \n\t"
> "start: \n\t"
> "lgdt r_gdt_descr \n\t"
> + "lidt r_idt_descr \n\t"
> "ljmp $8, $1f; 1: \n\t"
> ".code16gcc \n\t"
> "mov $16, %eax \n\t"
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [kvm-unit-tests PATCH 2/3] x86: realmode: hlt loop as fallback on exit
2020-06-26 9:23 [kvm-unit-tests PATCH 0/3] x86: realmode: fixes Nadav Amit
2020-06-26 9:23 ` [kvm-unit-tests PATCH 1/3] x86: realmode: initialize idtr Nadav Amit
@ 2020-06-26 9:23 ` Nadav Amit
2020-06-26 9:23 ` [kvm-unit-tests PATCH 3/3] x86: realmode: fix lss test Nadav Amit
2020-06-26 10:43 ` [kvm-unit-tests PATCH 0/3] x86: realmode: fixes Paolo Bonzini
3 siblings, 0 replies; 6+ messages in thread
From: Nadav Amit @ 2020-06-26 9:23 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: kvm, Nadav Amit
For systems without emulated devices (e.g., bare-metal), use halt-loop
when exiting the realmode test.
Signed-off-by: Nadav Amit <namit@vmware.com>
---
x86/realmode.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/x86/realmode.c b/x86/realmode.c
index ef79f7e..301b013 100644
--- a/x86/realmode.c
+++ b/x86/realmode.c
@@ -115,6 +115,10 @@ static int failed;
static void exit(int code)
{
outb(code, 0xf4);
+
+ while (1) {
+ asm volatile("hlt" ::: "memory");
+ }
}
struct regs {
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [kvm-unit-tests PATCH 3/3] x86: realmode: fix lss test
2020-06-26 9:23 [kvm-unit-tests PATCH 0/3] x86: realmode: fixes Nadav Amit
2020-06-26 9:23 ` [kvm-unit-tests PATCH 1/3] x86: realmode: initialize idtr Nadav Amit
2020-06-26 9:23 ` [kvm-unit-tests PATCH 2/3] x86: realmode: hlt loop as fallback on exit Nadav Amit
@ 2020-06-26 9:23 ` Nadav Amit
2020-06-26 10:43 ` [kvm-unit-tests PATCH 0/3] x86: realmode: fixes Paolo Bonzini
3 siblings, 0 replies; 6+ messages in thread
From: Nadav Amit @ 2020-06-26 9:23 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: kvm, Nadav Amit
Running lss with some random descriptor and then performing pop does not
work so well. Use mov instructions instead of push/pop pair.
Signed-off-by: Nadav Amit <namit@vmware.com>
---
x86/realmode.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/x86/realmode.c b/x86/realmode.c
index 301b013..90ecd13 100644
--- a/x86/realmode.c
+++ b/x86/realmode.c
@@ -1378,10 +1378,10 @@ static void test_lds_lss(void)
outregs.eax == (unsigned long)desc.address &&
outregs.ebx == desc.sel);
- MK_INSN(lss, "pushl %ss\n\t"
+ MK_INSN(lss, "mov %ss, %dx\n\t"
"lss (%ebx), %eax\n\t"
"mov %ss, %ebx\n\t"
- "popl %ss\n\t");
+ "mov %dx, %ss\n\t");
exec_in_big_real_mode(&insn_lss);
report("lss", R_AX | R_BX,
outregs.eax == (unsigned long)desc.address &&
--
2.20.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [kvm-unit-tests PATCH 0/3] x86: realmode: fixes
2020-06-26 9:23 [kvm-unit-tests PATCH 0/3] x86: realmode: fixes Nadav Amit
` (2 preceding siblings ...)
2020-06-26 9:23 ` [kvm-unit-tests PATCH 3/3] x86: realmode: fix lss test Nadav Amit
@ 2020-06-26 10:43 ` Paolo Bonzini
3 siblings, 0 replies; 6+ messages in thread
From: Paolo Bonzini @ 2020-06-26 10:43 UTC (permalink / raw)
To: Nadav Amit; +Cc: kvm
On 26/06/20 11:23, Nadav Amit wrote:
> Some fixes for realmode tests.
>
> Nadav Amit (3):
> x86: realmode: initialize idtr
> x86: realmode: hlt loop as fallback on exit
> x86: realmode: fix lss test
>
> x86/realmode.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 6+ messages in thread