diff options
| author | Jan Beulich <jbeulich@suse.com> | 2021-07-19 12:28:50 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2021-07-19 12:28:50 +0200 |
| commit | 471383ddd1843700fdd7d74242ba0e5f314dc678 (patch) | |
| tree | 11c06a76c5ef7235cb12035ab108ae6f1048781d /xen/arch/x86/msr.c | |
| parent | 0be5a00af590c97ea553aadb60f1e0b3af53d8f6 (diff) | |
x86/AMD: adjust SYSCFG, TOM, etc exposure to deal with running nested
In the original change I neglected to consider the case of us running as
L1 under another Xen. In this case we're not Dom0, so the underlying Xen
wouldn't permit us access to these MSRs. As an immediate workaround use
rdmsr_safe(); I don't view this as the final solution though, as the
original problem the earlier change tried to address also applies when
running nested. Yet it is then unclear to me how to properly address the
issue: We shouldn't generally expose the MSR values, but handing back
zero (or effectively any other static value) doesn't look appropriate
either.
Fixes: bfcdaae9c210 ("x86/AMD: expose SYSCFG, TOM, TOM2, and IORRs to Dom0")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Diffstat (limited to 'xen/arch/x86/msr.c')
| -rw-r--r-- | xen/arch/x86/msr.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c index 650d060b12..b834456c7b 100644 --- a/xen/arch/x86/msr.c +++ b/xen/arch/x86/msr.c @@ -367,7 +367,8 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t *val) goto gp_fault; if ( !is_hardware_domain(d) ) return X86EMUL_UNHANDLEABLE; - rdmsrl(msr, *val); + if ( rdmsr_safe(msr, *val) ) + goto gp_fault; if ( msr == MSR_K8_SYSCFG ) *val &= (SYSCFG_TOM2_FORCE_WB | SYSCFG_MTRR_TOM2_EN | SYSCFG_MTRR_VAR_DRAM_EN | SYSCFG_MTRR_FIX_DRAM_EN); |